modern-day whales

IMO D. Tense is correct in D.

E has error "their habitat"

C - error "with the sinking "

D says "evolving" and "forcing" into water happened at same time. do you think sentence intends that meaning

My choice is also D as I think that evolve...forced and ....when...sink is correct structure.

Though I would appreciate it if an expert can provide more clarity...

I think A and B is out as it is using "had evolved" , there are no two past occurrence happened.
Same way we can out C , E seems wordy and awkward

hi.
expert please comment on :A:. why is this wrong? we have two past event evolved and forced.
thanks

Let me try!

I read somewhere that if two events occur, GMAT preffers the usage of HAD for the event that occured in the distant past.

However, this sentence has some complex angles. Let me explain.

1) "That":

"That" is used to connect two clauses. In this sentence it connects "Fossil records reveal that modern-day whales had evolved from a land-dwelling ancestor" and "was forced into the water when its habitat sunk at the end of the Pleistocene period."

Since these are two separate clauses that have been merely connected by "that", we can put both the sentences in "simple past tense." There's no connection between the two clauses except the use of "that". Evolution of whales is an event that has nothing to do with what happened to its distant ancestors (gramatically, not scientifically). Hence, the use of "had" is unwarranted.

2) This brings me to my next point. Look at the second part of the sentence:

"that was forced into the water when its habitat sunk at the end of the Pleistocene period."

Now, "Forced into water" is one event, and "its habitat sunk" is another event. Does this mean that we should use "had"? NO. WHY? Because the sentence uses "when".

"When" is used to indicate two simultaneous events. The two events occured almost simultaneously. We do not prefer "had" in such cases.

THUS, we can reject A, B and C because they use "had" unnecessarily. (I hope this helps shweta.kalra)
The use of "their" in E is unwarranted.

My answer: D