Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: The cardiovascular system circulates blood through two different loops. Pulmonary circulation is a loop that carries blood between the heart and lungs. Systemic circulation is a loop that carries blood between the heart and the rest of the body. Answer: pulmonary and systemic
Output:
What are the two loops of blood flow in the cardiovascular system?