Which Statement About the Cardiac Cycle in Mammals Is True

Multiple Choice

Which statement about the cardiac cycle in mammals is true?

A) Only the ventricles contract in unison.
B) Only the atria contract in unison.
C) The atria contract in unison and the ventricles contract in unison.
D) Only the atrium and ventricle on the right side of the heart contract in unison.
E) Only the atrium and ventricle on the left side of the heart contract in unison.