Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: The bottom two chambers of the heart are called the left and right ventricles. The ventricles receive blood from the atria and pump it out of the heart, either to the lungs or to the rest of the body. Answer: ventricles
What structures receive blood from the atria and pump it out of the heart?