Australian embroyologists have found evidence that suggests that the elephant is descended from an aquatic animal, and its trunk originally evolved as a kind of snorkel.
A) that suggests that the elephant is descended from an aquatic animal, and its trunk originally evolved
B) that has suggested the elephant descended from an aquatic animal, its trunk originally evolving
C) suggesting that the elephant had descended from an aquatic animal with its trunk originally evolving
D) to suggest that the elephant has descended from an aquatic animal and its trunk originally evolved
E) to suggest that the elephant is descended from an aquatic animal and that its trunk originally evolved
I selected choice D, which turned out to be wrong. I guess I'm unclear why "is descended" is correct over "has descended". It seems as though the elephant was descended from the aquatic animal and continues to be so in the present. Perhaps it is simply an idiomatic thing.