Question

multiple choice question
the ventricles are _.
o the thicker lower chambers of the heart
earllke projections off of the atria
o valves in the heart
the thinner-walled upper chambers of the heart

Explanation:

The heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers). The ventricles have thicker walls than the atria because they need to pump blood out of the heart. The atria receive blood. Earlike projections off of the atria are auricles. Valves in the heart prevent backflow of blood. The thinner - walled upper chambers are the atria.

Answer:

the thicker lower chambers of the heart