The fact that fish, penguins, and dolphins all have the same basic shape is best explained by which of the following?

a) the basic shapes of fish, penguins, and dolphins are vestigial structures.

b) fish, penguins, and dolphins all faced the same physical constraints during their evolution andconverged upon the same body plan.

c) divergent evolution and adaptive radiation into new niches often result in convergent evolution.

d) the similarities are probably due to random chance.

e) parallel evolution is common among aquatic mammals

I would say it is E.

Explanation:

because fish, penguins, and dolphins are aquatic animals. It can't be A. because if it were vestigial it would be useless. It can't be B even though it does seem like the right answer because the are all aquatic. It can't be C. because it would been that the same species would have the same niche which is not possible. It can't be D. because every organism is evolved from a common ancestor.

B) Fish, penguins, and dolphins all faced the same physical constraints during their evolution and converged upon the same body plan

Explanation:

prokaryotic cells do not have a nucleus in which the dna is stored in, it floats freely inside the cell.

eukaryote cells do have a nucleus in which the dna is stored in.