instruction:
Given a scientific passage and an answer, generate a question for the given answer.
question:
Passage: Bacteria change nitrogen gas from the atmosphere to nitrogen compounds that plants can absorb. Answer: bacteria
answer:
What changes nitrogen gas from the atmosphere to nitrogen compounds that plants can absorb?

question:
Passage: Destructive interference in waves occurs when two troughs overlap. Answer: two troughs
answer:
Destructive interference in waves occurs when what things overlap?

question:
Passage: The organs that make up the cardiovascular system are the heart and a network of blood vessels that run throughout the body. The blood in the cardiovascular system is a liquid connective tissue. Figure below shows the heart and major vessels through which blood flows in the system. The heart is basically a pump that keeps blood moving through the blood vessels. Answer: cardiovascular system
answer:
The heart and a network of blood vessels that run throughout the body make up what organ system?