# geologists tried to determine rates of sedimentation so as to estimate the age of Earth



## 77Cat77

Hello, dear members!
My students ask me to counsel native speakers on the following question.
They cannot accept my explanation about choice B and choice C.

After Hutton, geologists tried to determine rates of sedimentation so as to estimate the age of Earth from the total length of the sedimentary, or stratigraphic, record. Typical numbers produced at the turn of the twentieth century were 100 million to 400 million years. These underestimated the actual age by factors of 10 to 50 because much of the sedimentary record is missing in various locations and because there is a long rock sequence that is older than half a billion years that is far less well defined in terms of fossils and less well preserved.

According to paragraph 4, what happened when geologists at the turn of the twentieth century tried to estimate Earth’s age?
A. They ignored Hutton’s findings about rates of sedimentation and thus tended to underestimate the age by a factor of 10 to 50.
B. Using the sedimentary record, they were able to guess the correct age within 100 million to 400 million years.
C. They did not realize that much of the sedimentary record is missing and thus assumed that Earth is much younger than it actually is.
D. They did not correctly calculate the rates of sedimentation and thus concluded that Earth is much older than it actually is.

source

C is not right, because the subject of the verb "assumed" is "they", which refers to geologists at the turn of the twentieth century. So, C is wrong, since it is the author that writes in the original text that "These underestimated the actual age by factors of 10 to 50".

The reason why I think Choice B, especially the word "correct", is acceptable is that, based on the record available to geologists of that time, the best they could guess is the age within 100 million to 400 million years. 

Check my explanation, please. Thank you very much!


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## Loob

C is right.
The early twentieth century geologists assumed the earth was younger than it is. 
Their calculations produced numbers that were too small.


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## Uncle Jack

77Cat77 said:


> the subject of the verb "assumed" is "they", which refers to geologists at the turn of the twentieth century.


This is correct. However, there is a clear sequence in the original passage. Geologists tried to estimate the age of the earth. Typical numbers produced (by geologists) at the turn of the century were 100 million years to 400 million years. These numbers underestimated the age of the earth by factors of 10 to 50 because much of the sedimentary record is missing.

It was the geologists who produced the numbers; it is therefore the geologists who underestimated the age of the earth, and the reason they underestimated the age of the earth is because they did not realise that much of the sedimentary record was missing.

"Correct" in B is an absolute. The correct age of the earth is about 4.5 billion years old. This isn't stated in the passage, but it is stated that the earth is at least ten times older than 400 million years.

There is, incidentally, a big clue that B is wrong, in that it says "within 100 million (years)". Nowhere does the original passage mention "within 100 million (years)", nor are there any numbers that can be construed as being within 100 million years (of anything else).


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## 77Cat77

Loob said:


> C is right.
> The early twentieth century geologists assumed the earth was younger than it is.
> Their calculations produced numbers that were too small.


I accept this: The early twentieth century geologists assumed the earth was younger than it is. 
But C expresses what they assumed is that " Earth is much younger than it actually is", which is actually expressed by the author.


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## 77Cat77

Uncle Jack said:


> It was the geologists who produced the numbers; it is therefore the geologists who underestimated the age of the earth, and the reason they underestimated the age of the earth is because they did not realise that much of the sedimentary record was missing.


This is what the author exactly says. But C expresses the assumption of geologists of that time is that Earth is much younger than it actually is.


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## Uncle Jack

77Cat77 said:


> But C expresses the assumption of geologists of that time is that Earth is much younger than it actually is.


They did assume this. What makes you think that they didn't?


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## 77Cat77

Uncle Jack said:


> They did assume this. What makes you think that they didn't?


Sorry, but they did not. It is the author says that geologists of that time underestimated the age.


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## Loob

I'm sorry, I don't really understand what you're saying, 77Cat77.

Are you referring to the verb tenses?

If so, then given that we're only talking about just over 100 years, there's no practical difference between:
_They assumed that Earth is much younger than it actually is.
They assumed that Earth was much younger than it actually is._
and
_They assumed that Earth was much younger than it actually was._


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## 77Cat77

Loob said:


> Are you referring to the verb tenses?


No, I am arguing that C is wrong because "that Earth is much younger than it actually is" is not the assumption geologists of that time made.


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## Loob

So is it the verb "assumed"? How would you feel if the sentence said "... and thus concluded that Earth is much younger than it actually is"?


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## 77Cat77

I'd say this is not right, either. No matter the verb is "concluded" or "assumed", the parallel structure in Choice C determines that the subject is "they", which refers to geologists of the twentieth century.


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## Roxxxannne

I think I see the problem. 
1)  [They] thus assumed that Earth is much younger than it actually is.
is *not *the same as 
2) [They] thus assumed "Earth is much younger than it actually is."

What they assumed was an incorrect age of the earth.


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## 77Cat77

Roxxxannne said:


> 1) [They] thus assumed that Earth is much younger than it actually is.
> is *not *the same as
> 2) [They] thus assumed "Earth is much younger than it actually is."


What's the difference between these two expressions? I beg your further explanation.


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## Roxxxannne

The first sentence is what an author, writing about the history of geological research, says about geologists in the early 20th century who made a particular assumption. 
The second sentence repeats what the geologists actually said. 

What happened when the geologists at the turn of the twentieth century tried to estimate Earth’s age?
They made an incorrect assumption: that Earth is much younger than it actually is.

"What happened when the geologists at the turn of the twentieth century tried to estimate Earth’s age?" (the TOEFL question) is a different question from "What did geologists at the turn of the 20th century say about the age of the Earth?"


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## 77Cat77

Roxxxannne said:


> The first sentence is what an author, writing about the history of geological research, says about geologists in the early 20th century who made a particular assumption.


Do you mean Choice C means: the author says that geologists in the early twentieth century assumed that Earth is much younger than it actually is?
Still, it's the geologists at the turn of the twentieth century who made the assumption, not mentioned in the text. They only estimated the Earth's age, which they thought was the correct age but actually, an underestimated one.


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## Loob

Here's a different example, in case it helps.

Let's say that today's temperature is 30 degrees but I assume it's 20 degrees.

These sentences are both true:
_I believe the temperature is lower than it actually is.
I assume the temperature is lower than it actually is._

I really *don't*, however, say to myself "The temperature is lower than it actually is".


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## Uncle Jack

77Cat77 said:


> They only estimated the Earth's age, which they thought was the correct age but actually, an underestimated one.


There is no difference between "thought" and "assumed" in this context. I don't see why you are happy to say "which they thought was the correct age" but are unwilling to say "They [...] assumed that Earth is much younger than it actually is".


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## 77Cat77

Loob said:


> Here's a different example, in case it helps.
> 
> Let's say that today's temperature is 30 degrees but I assume it's 20 degrees.
> 
> These sentences are both true:
> _I believe the temperature is lower than it actually is.
> I assume the temperature is lower than it actually is._
> 
> I really *don't*, however, say to myself "The temperature is lower than it actually is".


I agree that your sentences are perfectly fine! But, the premise is that you know the actual temperature. But geologists of that time did not know the actual age of the Earth.


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## 77Cat77

Uncle Jack said:


> There is no difference between "thought" and "assumed" in this context. I don't see why you are happy to say "which they thought was the correct age" but are unwilling to say "They [...] assumed that Earth is much younger than it actually is".


We now know the actual age of the Earth, but they did not. So, we, as well as the author, have the basis to say that their estimation is not right. But how could they? 
I would agree with Choice C If it is phrased as "They did not realize that much of the sedimentary record is missing and thus the age of the Earth they assumed is much younger than it actually is"


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## Loob

77Cat77 said:


> But, the premise is that you know the actual temperature.


That's where you're going wrong....

Let's put someone else into my previous example: the first person "I" may have been confusing.
------------------​Today's temperature is 30 degrees but Michael assumes it's 20 degrees.​​These sentences are both true:​_Michael believes the temperature is lower than it actually is._​_Michael assumes the temperature is lower than it actually is._​------------------​​There is absolutely no suggestion there that Michael knows what the correct temperature is.  Nor is there any suggestion that he knows his belief/assumption is an underestimate.


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## 77Cat77

Loob said:


> _Michael believes the temperature is lower than it actually is.Michael assumes the temperature is lower than it actually is._


Are these sentences the same as The temperature Michael believes/assumes is lower than it actually is?


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## grassy

77Cat77 said:


> The temperature Michael believes/assumes is lower than it actually is


It's incorrect (assuming it's meant to be a complete sentence ).


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## Loob

77Cat77 said:


> Are these sentences the same as The temperature Michael believes/assumes is lower than it actually is?



Not quite.

Maybe it would help to see the logic as being:

_Michael believes the temperature is X.  X is lower than the temperature actually is.
Michael assumes the temperature is X.  X is lower than the temperature actually is._


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## Uncle Jack

77Cat77 said:


> I would agree with Choice C If it is phrased as "They did not realize that much of the sedimentary record is missing and thus the age of the Earth they assumed is much younger than it actually is"


Ah, I think I see the problem. What they assumed is the age of the earth. They did not assume (as a separate thing) what the age of the earth actually is. However, sentence C is ordinary English, where someone's assumption includes a fact (using "be") of which the person was ignorant.

I think you agree with this statement:
They assumed that the Earth is 100 million to 400 million years old.​I imagine that you agree with this statement too:
100 million to 400 million years old is much younger than the Earth actually is.​These two statements can be combined in English to give:
They assumed that the Earth is much younger than it actually is.​
It might have been better if their assumption used the past tense "was" whereas the fact (at least, we assume it is a fact) of the Earth's age used "is":
They assumed that the Earth was much younger than it actually is.​This change in tense is not essential in English, but it does help separate assumptions at the time from facts that are supposedly true for all time.


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## 77Cat77

Uncle Jack said:


> I think you agree with this statement:
> They assumed that the Earth is 100 million to 400 million years old.


yes


Uncle Jack said:


> I imagine that you agree with this statement too:
> 100 million to 400 million years old is much younger than the Earth actually is.


yes


Uncle Jack said:


> These two statements can be combined in English to give:
> They assumed that the Earth is much younger than it actually is.


It is difficult for me to get across this combination. How about this: They said that the Earth is much younger than it actually is.
I think it means What they said is "the Earth is much younger than it actually is".


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## 77Cat77

Loob said:


> Not quite.
> 
> Maybe it would help to see the logic as being:
> 
> _Michael believes the temperature is X.  X is lower than the temperature actually is.
> Michael assumes the temperature is X.  X is lower than the temperature actually is._


I see the logic but why they can be combined?
Michael says the temperature is X.  X is lower than the temperature actually is.
Can they be combined as followed?
Michael says the temperature is lower than the temperature actually is. ❓


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## Uncle Jack

77Cat77 said:


> It is difficult for me to get across this combination. How about this: They said that the Earth is much younger than it actually is.
> I think it means What they said is "the Earth is much younger than it actually is".


Indirect speech is always a paraphrase, and I cannot stress this highly enough. Unless something is written in quotation marks, you cannot reconstruct direct speech from indirect speech; the best you can do is make a guess.

Suppose they said, "The Earth is between 100 million and 400 million years old."

This could be reported as:
They said that the Earth was between 100 million and 400 million years old.​They said that the Earth was much younger than it actually is.​
Obviously the second option could not have been written till much later, when we had other methods of calculating the age of the Earth.

The original question is not about indirect speech, but you can use "they assumed" in a similar way.


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## 77Cat77

Uncle Jack said:


> Obviously the second option could not have been written till much later, when we had other methods of calculating the age of the Earth.


This is the reason I think Choice C contains information that is obviously wrong.
Choice C should be adapted as:
... and thus the ages of the Earth geologists of the 20th century suggested are much younger than it actually is.


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## Uncle Jack

77Cat77 said:


> This is the reason I think Choice C contains information that is obviously wrong.
> Choice C should be adapted as:
> ... and thus the ages of the Earth geologists of the 20th century suggested are much younger than it actually is.


But the passage was written in modern times, so it uses modern knowledge, and this information can be freely inserted into sentences about the past. This is how the English language works.


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## Loob

77Cat77 said:


> I see the logic but why they can be combined?
> Michael says the temperature is X.  X is lower than the temperature actually is.
> Can they be combined as followed?
> Michael says the temperature is lower than the temperature actually is. ❓


Yes (except that we probably wouldn't repeat 'temperature' in the combined sentence):
_Michael says the temperature is lower than it actually is._

The person who says or writes the sentence "Michael says the temperature is lower than it actually is" knows that Michael is wrong.


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## 77Cat77

Uncle Jack said:


> But the passage was written in modern times, so it uses modern knowledge, and this information can be freely inserted into sentences about the past. This is how the English language works.


I agree that the author can freely insert factual information into the text. But Choices are written by test makers not the author. Test takers should find out whether each choice is true or false based on the original text. We can only see in the paragraph that the author comments that these numbers underestimated the Earth's age. 


Loob said:


> _Michael believes the temperature is lower than it actually is.Michael assumes the temperature is lower than it actually is._


Michael only assumes the temperature is 20. Michael did not make the assumption that the temperature is lower than it actually is.
If we asked Michael,"are you making the assumption that the temperature is lower than it actually is?", I don think he would agree.


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## Loob

77Cat77 said:


> If we asked Michael,"are you making the assumption that the temperature is lower than it actually is?", I don think he would agree.


No, he wouldn't.
Michael only says "I assume the temperature is 20 degrees".
Michael doesn't know he's wrong.
It is the speaker/writer of the sentence "Michael assumes the temperature is lower than it actually is" who knows that Michael is wrong.


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## 77Cat77

Loob said:


> Michael assumes the temperature is lower than it actually is"


I would agree if the first "is" is deleted. Michael assumes a temperature is lower than it actually is.


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## Thomas Tompion

77Cat77 said:


> The reason why I think Choice B, especially the word "correct", is acceptable is that, based on the record available to geologists of that time, the best they could guess is the age within 100 million to 400 million years.


But it cannot be correct in any sense, because we are told _ex post_ that they miscalculated by a factor of 10 to 50.


77Cat77 said:


> C is not right, because the subject of the verb "assumed" is "they", which refers to geologists at the turn of the twentieth century. So, C is wrong, since it is the author that writes in the original text that "These underestimated the actual age by factors of 10 to 50".


C states _They did not realize that much of the sedimentary record is missing and thus assumed that Earth is much younger than it actually is._

You can't accept this, Cat77, as correct.  It's true that it would be more accurate to say that they concluded that Earth is much younger than it actually is.  The fact is that loose writers do occasionally use _assume_ for _conclude_ in similar circumstances.

I find C flawed, for the reason I have just given, but the other 3 distracters contain much more serious flaws.


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## Thomas Tompion

77Cat77 said:


> Michael assumes a temperature is lower than it actually is.


I think it would be more usual to say _Michael assumes the temperature to be lower than it actually is._

Again, I'd question your use of _assume_: surely he's acting on evidence?


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## 77Cat77

Thomas Tompion said:


> But it cannot be correct in any sense


X: Which choice do you think is correct?
Y: I guess the correct choice is A.
Z: No, the correct choice is B.

In this conversation,  only the correct choice in green is the actual correct one. The red one happens in Y's guessing.


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## 77Cat77

Thomas Tompion said:


> Michael assumes the temperature to be lower than it actually is


Thank you for your correction.
Is your sentence above equivalent to "Michael assumes that the temperature is lower than it actually is"?


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## Thomas Tompion

77Cat77 said:


> X: Which choice do you think is correct?
> Y: I guess the correct choice is A.
> Z: No, the correct choice is B.
> 
> In this conversation,  only the correct choice in green is the actual correct one. The red one happens in Y's guessing.


You've lost me here.

There are two very obvious points:

1. Some people say_ I guess_, when they mean _I think_ (ie. it is my opinion).
2. Some people say _the correct choice is_, when they mean _it is my opinion that the correct choice is_.

I was surprised that you felt you could draw any conclusions from the conversation at all.


77Cat77 said:


> Is your sentence equivalent to "Michael assumes that the temperature is lower than it actually is"?


Yes.  But remember to distinguish between assumptions, and conclusions.


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## 77Cat77

Thomas Tompion said:


> 2. Some people say _the correct choice is_, when they mean _it is my opinion that the correct choice is_.


I’m sorry. The conversation should be as followed. X knows the correct answer is B.

X: Which choice do you think is correct?
Y: I *think* the correct choice is A.
*X*: No, the correct choice is B.


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## Loob

77Cat77,  the bottom line, I'm afraid, is that: 
- C is a correctly-formulated sentence in English (though TT has a point about "concluded" being more accurate than "assumed")
- C is also the right answer.


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## 77Cat77

Loob said:


> C is a correctly-formulated sentence in English


Grammatically I agree it is a correctly formulated sentence. But if, without any background information, I see the sentence "Michael assumes that the temperature is lower than it actually is", I may infer that Michael suggested a temperature, that he knows the actual temperature, and that the one he suggested is lower than the actual one.


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## Loob

Then your inference would be wrong (see post 32).

And here, of course, we have background information.


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## Leeeroy

Try this simplified version:

Geologists attempted to guess Earth's age using various data points. The average guess was between 100M and 400M years, a gross underestimation: unbeknown to the geologists, they were guessing based on incomplete data.

What's up?
A) Important findings were ignored on purpose.
B) Geologists managed to guess the age correctly (give or take 400M years, no biggie).
C) Geologists did not realize that something was missing and thus assumed that Earth was much younger than it actually was.
D) Geologists' errors made them overestimate Earth's age.

As you can see,

A introduces a random new idea;
B misinterprets 100-400M as the estimates' margin of error;
C roughly summarizes the paragraph;
D directly contradicts the text.


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## 77Cat77

Leeeroy said:


> B) Geologists managed to guess the age correctly (give or take 400M years, no biggie).


This is what exactly happened when geologists at the turn of the twentieth century tried to estimate Earth’s age?


Leeeroy said:


> C) Geologists did not realize that something was missing and thus assumed that Earth was much younger than it actually was.



to take for granted or without proof; 
suppose;
postulate;
posit:
to assume that everyone wants peace.

WordReference Random House Unabridged Dictionary of American English © 2021

Geologists took for granted that Earth was much younger than it actually was. 
They did not do this during that time.

Choice C should be modified as followed.

C) Geologists did not realize that something was missing and thus falsely assumed that the Earth's age is within 100 million to 400 million years.


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## 77Cat77

Loob said:


> Then your inference would be wrong (see post 32).
> 
> And here, of course, we have background information.



to take for granted or without proof;
suppose;
postulate;
posit:
According to the definition given by WordReference Random House Unabridged Dictionary of American English © 2021

Choice C equals to:
They did not realize that much of the sedimentary record is missing and thus take for granted that Earth is much younger than it actually is.

But they only took for granted that the age of the Earth fell in between 100 million to 400 million years. This is what really happened when geologists at the turn of the twentieth century tried to estimate Earth’s age


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## 77Cat77

I'm sorry for bothering you with this question. And I really appreciate your help. All of you are so kind to have given me your advice. Please dismiss me If you feel upset.


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## Leeeroy

77Cat77 said:


> This is what exactly happened when geologists at the turn of the twentieth century tried to estimate Earth’s age?


What happened was that they estimated that Earth is somewhere between 100M and 400M years old.

This estimate was incorrect.

This is why option B ("...they were able to guess the correct age...") is incorrect. The geologists did not guess correctly. They did not guess the correct age. They guessed a number of incorrect ages. And they weren't even close with any of these guesses.

You can rewrite each of the four options in a million different ways but they're all just fine just the way they are right now. There is no problem with the text or any of the four options.


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## Loob

I'm not sure there's much more we can do to help, 77Cat77.

I think the problem is that you're reading
_C. They [...] assumed that Earth is much younger than it actually is._
as if it meant
_Ci. They [...] assumed: "Earth is much younger than it actually is"._

C doesn't mean Ci.

Similarly:
_They concluded that Earth is much younger than it actually is_ does not mean_ They concluded: "Earth is much younger than it actually is"._

The red sentences make sense; the blue ones don't.


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## Edinburgher

There seems to be a basic misunderstanding on your part somewhere, 77Cat77, and we are having trouble finding where this is. I don't think it can be what Rox said in #12 and Loob repeated in #48, because the blue statements are clearly patently absurd and impossible.

Option C is technically incorrect (as Loob pointed out in #10) because the word "assumed" is wrong and should have been "deduced" or "concluded", but we are supposed to ignore that mistake, so let's just pretend C used "concluded".

Here are several facts that the main text tells us:
The early 20th century geologists did not know how old the Earth was.
They wanted to estimate the age on the basis of sedimentation data.
Their calculations led them to conclude that the age was between 100 and 400 million years.
This conclusion was wrong.  We know, but they did not, that the age is actually about 10 to 50 times that much.
The reason for their error was that their calculations used incomplete data.

You agree that statements A and D are wrong.  Let's look at B and C.

_B. Using the sedimentary record, they were able to guess the correct age *within* 100 million to 400 million years._
What does this mean?  To guess something correctly *within* X means the guess *differs* from the correct value *by no more than* X.
Because we know (or think we know) that the age is actually about 4500 million years, B means that their estimate must have been at best between 4400 and 4600 million years, or at worst between 4100 and 4900 million years.  But that wasn't their estimate.  Their calculations led them to believe that *the age was* between 100 and 400 million years.  *B is therefore incorrect.*

_C. They did not realize that much of the sedimentary record is missing and thus *concluded* that __Earth is much younger than it actually is._
What does this mean?  This is just another way of saying that their conclusions were incorrect: their calculations greatly underestimated the age.
This is entirely consistent with the facts from the text:  The age, as far as we know, *is actually* 4500 million years, but their conclusions were that the age was 100-400 million years.  Therefore they thought the age was younger than it *actually is*, by an amount of between 4100 and 4400 million years, or by a factor of between about 11 and 45.  *C is therefore correct.*


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## kentix

I think the use of "assumed" is completely wrong so none of the answers are correct, in my estimation. B is certainly wrong but assumed and concluded (or believed) are not interchangeable, _especially_ when the topic is science. I give the testmakers a failing grade and _conclude_ they don't know what they are doing.

This is what C should have been:

C. They did not realize that much of the sedimentary record is missing and thus came to the conclusion that Earth is much younger than it actually is.​
Or

C. They did not realize that much of the sedimentary record is missing and thus believed that Earth is much younger than it actually is.​
The thing they expressly were not doing was assuming. They were doing science, the opposite of assuming.

B is wrong because the paragraph is talking about their belief of the absolute age of the Earth, which they believed by measurement and data analysis was somewhere between 100 million years old and 400 million years old. But B is talking about error bars, how far away from the true age their estimate was. B says it was within 100 to 400 million years of the true age of the Earth. And the paragraph says nothing like that.


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## Leeeroy

_Ancient Romans assumed that Earth was flat_. I'm sure they had their (what-passed-as-)scientific(-at-the-time) ways to prove it, but we know better than to treat that nonsense seriously. Flimsy evidence is no evidence; the word was used appropriately.

The scientists themselves wouldn't have used the word _assume_, sure, nor would've anyone commenting/reporting on their findings at the time, but it was perfectly acceptable for the author of the question, with the benefit of additional research, to dismiss the geologists' factually incorrect conclusions as assumptions because that's what they are when viewed through the lens of modern science.


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## Edinburgher

To be fair, the distinction between an assumption and a conclusion becomes moot when the output of one piece of science (a conclusion) then becomes an input to a new piece of science.  Once we have concluded or proved something, we can then assume it in later steps.


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## Roxxxannne

Leeeroy said:


> _Ancient Romans assumed that Earth was flat_. I'm sure they had their (what-passed-as-)scientific(-at-the-time) ways to prove it, but we know better than to treat that nonsense seriously. Flimsy evidence is no evidence; the word was used appropriately.
> 
> The scientists themselves wouldn't have used the word _assume_, sure, nor would've anyone commenting/reporting on their findings at the time, but it was perfectly acceptable for the author of the question, with the benefit of additional research, to dismiss the geologists' factually incorrect conclusions as assumptions because that's what they are when viewed through the lens of modern science.


EDITED
I'd like to put in a word for the nonsense of "the ancients." Roman scientists (and Greeks before them) knew perfectly well that Earth was not flat.
Also, they did not _assume _Earth was spherical; they deduced it from astronomical observation.

A modern right-thinking scientist who reads an earlier scientist's writings and finds a mistake in them that renders the result incorrect would not say the earlier scientist had assumed something.  They'd say the earlier scientist had made a mistake in the course of their research.  Or, if the earlier scientist was operating without modern instruments (as Greek and Roman astronomers did), the modern scientist might say that the earlier one had assumed something that was not correct (the distance of Earth to the sun, or the location of a point on the surface of Earth relative to the equator), but I doubt that they would say that the _result_ of a scientific approach was itself an assumption.


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## kentix

Roxxxannne said:


> A modern right-thinking scientist who reads an earlier scientist's writings and finds a mistake in them that renders the result incorrect would not say that the earlier scientist had assumed something.  They'd say the earlier scientist had made a mistake.




Being mistaken due to incomplete data is not the same as making an assumption. Even 200 years later. They were using a scientific method to get an answer. That is not assumption.

The one assumption mentioned that they did make was that they had access to all the relevant data. They did not. That was the mistake. That still doesn't make their scientific answer an assumption. It just makes it inaccurate.


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## 77Cat77

Edinburgher said:


> To guess something correctly *within* X means the guess *differs* from the correct value *by no more than* X.





kentix said:


> But B is talking about error bars, how far away from the true age their estimate was.


Oh! I did not know that's what _within_ means in Choice B! Now I see. Thank you very much!


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## Edinburgher

77Cat77 said:


> Oh! I did not know that's what _within_ means in Choice B! Now I see.


OK, so having convinced you that B is wrong, do you understand why C is right (other than because A, B, and D are wrong)?


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## 77Cat77

Edinburgher said:


> OK, so having convinced you that B is wrong, do you understand why C is right (other than because A, B, and D are wrong)?


I accept the difference between _assume_ and _conclude_. But even so, I cannot be convinced that there is any difference between _they concluded that the Earth is younger than it actually is _and _they concluded: "the Earth is younger than it actually is"_.

I'd rather it is: thus they suggested ages of Earth that are younger than it actually is.


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## JulianStuart

77Cat77 said:


> _they concluded: "the Earth is younger than it actually is"_.


This is not something someone would say, it is internally self-contradictory - can you explain how you understand this?  They did not know how old it "is" so they couldn't make a statement like this.


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## 77Cat77

JulianStuart said:


> They did not know how old it "is" so they couldn't make a statement like this.


I think it wrong for exactly this reason.


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## Roxxxannne

The meaning of
_They _<verb of thinking, believing, saying> _that the sky is blue. _(indirect statement/indirect speech)
is the same as
_They_ <verb of thinking, believing, saying>,_ "The sky is blue." _(direct statement/direct speech)
But _*in this particular case*
They concluded that Earth is younger than it actually is_
is not an example of indirect speech, it's a statement made by the author about the earlier geologists' conclusion.


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## Edinburgher

77Cat77 said:


> I cannot be convinced that there is any difference between _they concluded that the Earth is younger than it actually is _and _they concluded: "the Earth is younger than it actually is"_.


The difference is that the first wording means _they concluded that the Earth is younger than* we* (in 2021)* know it is*_.  This is a good, normal, non-contradictory statement.  They (in 1900) concluded the Earth is 100-400 M years old, while we (in 2021) know it is 4500 M years old.

The second wording means _they concluded that the Earth is younger than *they* (in 1900) *knew it is*._  This is nonsense because they didn't know or even claim to know how old it actually is.  That's what they were trying to discover with their calculations!  As a result of their calculations they concluded that it was 100-400 M years old, and *then* they thought they knew the age.  It is only *we* who can know that they were mistaken.


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## JulianStuart

77Cat77 said:


> I think it wrong for exactly this reason.


So it is different from the other version you wrote in #57, which does make sense, as Edniburgher noted above.


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## PaulQ

kentix said:


> I think the use of "assumed" is completely wrong so none of the answers are correct,


I'm sorry you had an electric shock when you were repairing the switch: I pulled the fuse and tested the switch - the light did not come on, therefore I *[wrongly] *assumed that the electricity was off. It turns out that the bulb had blown."



77Cat77 said:


> C. They did not realize that much of the sedimentary record is missing and thus *[wrongly] *assumed that Earth is much younger than it actually is.



The word "wrongly" is omitted, but is not necessary in the example as we are told that the geologists were off by a factor of 10 to 50.

OED:
Assume:  *10.  transitive. To take for granted as the basis of argument or action; to suppose:*
1869   E. A. Freeman _Hist. Norman Conquest _ (1876) III. xiii. 294   William assumes the willingness of the Assembly.

This is a test of comprehension and the OP has demonstrated its value.


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## Roxxxannne

PaulQ said:


> This is a test of comprehension and the OP has demonstrated its value.


Amen!


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## kentix

You _thought_ the electricity was off because you tested it. You didn't assume it.

"I saw John working on the wiring and because he's very careful and conscientious I assumed that he had turned the electricity off. So I was surprised to see him jump when he got a big shock."

You did no investigating of the electric system. You based your conclusion on past information about John's habits, not current information about the system.

Those scientists based their conclusion on the latest direct information they had, not on past beliefs carried forward. What they did was the opposite of relying on old beliefs and assumptions.


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## PaulQ

kentix said:


> You didn't assume it.


I did. I assumed you knew that. The point is, I believe/assume, that it was a false assumption - we all do that.


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## kentix

Measuring rocks (doing an experiment) to overturn previous assumptions is not assuming anything. I don't know how to say it more plainly.


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## elroy

77Cat77 said:


> My students ask me to counsel native speakers on the following question.





77Cat77 said:


> I cannot be convinced that there is any difference between _they concluded that the Earth is younger than it actually is _and _they concluded: "the Earth is younger than it actually is"_.


You have consulted (not counseled) native speakers, who have *unanimously* told you that C is without a doubt the correct answer and have gone to great lengths to explain why, yet you still "cannot be convinced."   Unfortunately, if you remain unconvinced, you will continue with a grave misunderstanding about English and you will be sorely misleading your students.  It would behoove you to reconsider.

I'll give it a shot myself and hopefully the penny will drop.

Let me start by saying that when I read the question and the answer choices, I didn't have to think about this for more than a nanosecond before identifying C as the right answer.  To a native speaker, the answer is _glaringly_ obvious, and this question is a no-brainer.  This is just to show you that there's not even a shred of ambiguity here: C is clearly and unequivocally the right answer.

Okay, here's my attempt:

They did not realize that much of the sedimentary record is missing and thus assumed that Earth is [X].

X = _a certain number of years old _

We today know that

X = _much smaller than the actual age of the earth _

Sentence C is simply plugging in (something that amounts to) the blue version for X, instead of the green version.  This doesn't change the truth value of the statement, because the blue version and the green version both express X.

They did not realize that much of the sedimentary record is missing and thus assumed that Earth is [_much younger than it actually is_].

This is perfect, clear, unambiguous English.

Here's another example:

I'm 50 and I don't have any gray hair.  I met Sally last week.  Because I don't have any gray hair, Sally thought I was in my thirties.​*Sally thought I was younger than I actually am.*​​Sally thought I was [Y].​​Y = _30-39_​​Y = _younger than I actually am_​​Sally thought I was [_younger than I actually am_].​
This is how English works.  If you don't accept this, you are doing yourself a disservice.


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## 77Cat77

elroy said:


> Sally thought I was [Y].Y = _30-39_Y = _younger than I actually am_Sally thought I was [_younger than I actually am_].


Crystal clear!
Now I have a better understanding of direct and indirect speeches.


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## 77Cat77

Thank you for going so far as to explain this point.
Your efforts are not saving me, but my students.
I appreciate every single word which you spare time typing.
Sorry for having upset you.


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## elroy

I wasn’t upset.  I was hoping you would see the light.


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