The lower chambers of the heart are the

septum
ventricles
atrium
pacemakers

The correct answer is - ventricles

Explanation:

A normal human heart has four chambers, two upper and two lower chambers. The upper chambers, known as the right atria and left atria that get incoming blood into the heart.

The lower chambers knowns as right ventricles and left ventricles that push the blood out of your heart to the rest of the body. Ventricles receive the blood from the atrium and pump or expel the blood to the rest of the body.

Thus, the correct answer is - ventricles.

the answer is c

explanation:

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands