A theory argues that racial differences can lead to differences in cra

I'm not able to get the conclusion of the argument, Please explain me. and Why BF1 is not an evidence?

goforgmat Thanks for the reply
Yes, I understand about evidence now a bit more . But still not convinced for the below statement. If the result is from the another study can't it be verified and considered as undeniable?
"another study suggests that humans who grow up farther from the equator are exposed to less ambient sunlight and therefore develop larger eyes, which in turn lead to larger visual cortices, increasing total brain size"

absolutely, but when another person verifies it doesn't have to come out to be absolute truth.
For example ,the author of the study stating that claim is a fact , but the claim itself doesn't have to be. It can happen that the way a study is conducted may not be fool proof. the Author could have drawn false conclusion .
Remember that when a researcher conducts studies ,he studies certain parameters their co-relation or causation and then draws conclusion. It is possible that it can be absolutely true or just a false conclusion. In this case we cannot say it is a fact.
Fact must be undeniable.

Go through some basic concepts related to BF question ,it will be more clear.

Official Explanation

Reading the question: since we have boldfaced text, we don't need to analyze the argument. We will just identify the logical role of each sentence.

Sentence

Starts With.../Includes...

Function

1st

"A theory argues"

States a theory

2nd

"However, another study suggests that humans"

States another theory

3rd

"Since the populations"

Fact

3rd

"data that appear to support the racial theory"

Opinion about theories

Sentence 1 states a theory, and sentence 2 states another theory; the bold part is the content of the belief of the second theory. Then we have some un-bolded evidence, and then the conclusion, in bold, the first hint of the author's opinion, which is a comparison of the theories.

Applying the filter: Let's see which answer choices get the first statement right. The first statement isn't an objection or evidence. That leaves only (D) and (E). The author's position is that evidence for the racial theory could be construed as support for the ambient-light theory. The author favors the ambient-light theory, which is expressed in the first statement. So the two bolded statements are in harmony. That rules out (D), and also confirms that (B) and (C) are out. And the first statement definitely isn't an objection, so (A) is out.

The correct answer is (E).