A paleontologist finds a fragment of a fossilized vertebrate that indicates that the animal had a three-chambered heart.The animal could have been a(n)
A) fish.
B) amphibian.
C) crocodile.
D) bird.
E) mammal.

Question

Quizplus · Accepted Answer

Fish have two-chambered hearts, while amphibians have three-chambered hearts. Crocodiles, birds, and mammals have four-chambered hearts. Therefore, the best choice is B, amphibian.

A Paleontologist Finds a Fragment of a Fossilized Vertebrate That