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

Question

Quizplus · Accepted Answer

Fish have a single circulatory system with a heart that typically has two chambers, but some ancient fish had a four-chambered heart in a single circuit. Other vertebrates like amphibians, crocodiles, birds, and mammals have a double circulatory system.

A Paleontologist Finds a Fragment of a Fossilized Vertebrate That