Explanation

The “Yet” that begins the second sentence indicates that Wills’ position would be supported by evidence that the newer parasites are in humans, the more harmful they are. So Wills’ position must be that more recent parasites are especially harmful, implying that “malignant” is the correct choice for the first blank. What follows “therefore” is a potential explanation for the trend that Wills expects, namely an evolution toward harmlessness, implying “benignity” for the third blank, with newer species having had “insufficient” time (second blank) to evolve toward harmlessness.
Thus, the correct answer is malignant (Choice B), insufficient (Choice E), and benignity (Choice H).
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The question had medium tag as difficulty. However, it is hard indeed.

The “Yet” that begins the second sentence indicates that Wills’ position would be supported by evidence that the newer parasites are in humans, the more harmful they are.

the clue is Yet.

Actually, the overall meaning is that parasites mute them into harmless host if stay longer inside humans. However, we do not have enough information to ascertain this with certainty. It is just another supposition.

Now is more clear ??

The key to solve TC is to catch as close as possible the meaning of the sentence as whole.

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It is the GRE (by ETS) Official Guide 2nd edition.

There is also the latest, the 3rd Editon but it is identical to the second edition.

look here to see all the questions from the Official Guides and relative questions explained

https://greprepclub.com/forum/the-offic ... -8020.html

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