As genetics researchers achieve greater success in their

I would be inclined to go with A.

What is the OA?

Meaning: genetic researchers achieve greater success in mapping exact locations and functions of human genes and thereby helps in understanding close connection between genes and birth defects..

B is out as in first part of sentence, it is clear that a fact is being spoken about. Had become in past perfect has no business here
Option C,D: has been becoming...present continous perfect tense...why use for a simple fact or statement. No use

Down to A and E. Again we are talking about fact that mapping has led to better understand of close connection so the use of has become (present perfect) is not correct.

E is clear winner

HAVE DONE happens before DO
so,

have done is not logic inhere.

First of all we need between as we are comparing two things i.e genes and birth defect.(Eliminate C)
The sentence states As genetics researchers.....The process is still going on and thus 'becomes' is perfect here.

+1 for E.

Hi

I am not clear about not using present perfect. @e-gmat.

Hi anks2190

I would like to give my 2 cents here.
I hope it helps.

Simple present Tense is used in describing things :
1.that happens routinely
2.facts
3.Truths that remain true over time.

If you read non-underlined portion of the Sentence, "As genetics researchers achieve greater success in their attempt to map the exact locations and functions of human genes, the"
This portion falls under the 3rd point of Simple present tense.. It means its something which is done by researchers and it holds true over the period of time.

Now, coming to your question , We cannot use present perfect tense here because Present perfect tense is used in describing event that began in past and continues in Present.

Non-Underlined portion suggests that researchers have achieved it and its a fact or you can say its a truth which remains true even now.

So with the simple present tense in the non-underlined part we want find the same from the given choices for underlined part as well to match the tense.

E fits our requirement because its simple present which describes truth or fact which is true always.


I hope that above explanation helps.

Official Explanation

Read the Original Sentence Carefully, Looking for Errors:

There is a problem with verb tense agreement in this sentence. If the error isn’t evident at first reading, going through the next steps will be helpful.

Scan and Group the Answer Choices:

The answer choices are different in several ways. The main differences involve the verbs used at the end of the underlined portion. (A) and (B) use “has become,” while (C) and (D) use “has been becoming,” and (E) uses “becomes.” If these differences aren’t enough to find the correct answer to the problem, you can look for other differences.

Eliminate Choices Until Only One Remains:

Logically, both parts of the sentence must be going on in the present. The genetics researchers “achieve greater success,” so the connection between genes and birth defects must also be in the present. There is no need to switch to the past tense “has become” or “has been becoming” as choices (A) through (D) do. (E) is correct.

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