instruction:
Given a scientific question, generate a correct answer to it.
question:
When leaves wilt, what plant process ceases?
answer:
photosynthesis

question:
The urea cycle, a set of biochemical reactions that produces urea from ammonium ions to prevent toxicity, occurs to some extent in the kidney, but primarily in what organ?
answer:
liver

question:
What types of drugs affect the brain and influence how a person can feel, think, or act?
answer:
psychoactive