Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Some sunlight is good for your health. Vitamin D is made in the skin when it is exposed to sunlight. But getting too much sun can be unhealthy. A sunburn is a burn to the skin that is caused by overexposure to UV radiation from the sun's rays or tanning beds. Answer: vitamin d
Output:
Which vitamin is made in the skin when it is exposed to sunlight?