Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.

A. which, causing plant and animal extinctions, marks

B. which caused the plant and animal extinctions and marks

C. and causing plant and animal extinctions that mark

D. an event that caused plant and animal extinctions, which marks

E. an event that caused the plant and animal extinctions that mark

In-depth Explanation and Correct Answer Below (so you don’t see it while reviewing the question)

Sixty-five million years ago, according to… Explanation

Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.

(A) which, causing plant and animal extinctions, marks

“North America” didn’t cause anything.

(B) which caused the plant and animal extinctions and marks

“North America” didn’t cause anything.

(C) and causing plant and animal extinctions that mark

This might work if there was a list SLAMMED and CAUSED. Otherwise it isn’t parallel.

(D) an event that caused plant and animal extinctions, which marks

Subject verb agreement. Plant and animal extinctions MARK.

(E) an event that caused the plant and animal extinctions that mark

Correct Answer: E

For some SC guidance, here’s a link to a breakdown of GMAT sentence correction.