Definition: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: The second stage of photosynthesis takes place in the stroma surrounding the thylakoid membranes of the chloroplast. The reactions of this stage can occur without light, so they are sometimes called light-independent or dark reactions. This stage of photosynthesis is also known as the Calvin cycle because its reactions were discovered by a scientist named Melvin Calvin. He won a Nobel Prize in 1961 for this important discovery. Answer: calvin cycle
Output:
Which cycle is named after the scientist melvin calvin?