Given a scientific passage and an answer, generate a question for the given answer.

Ex Input:
Passage: The bodies of organisms can make a sedimentary rock. Plant bodies are lithified to become coal. When shells are cemented together they make a type of limestone. So limestone can be considered chemical or organic. Answer: coal

Ex Output:
What is formed when plant bodies are lithified?


Ex Input:
Passage: Gaseous nitrogen is converted into forms that can be used by plants during the process of nitrogen fixation. Answer: nitrogen fixation

Ex Output:
Gaseous nitrogen is converted into forms that can be used by plants during a process called what?


Ex Input:
Passage: We can see rainbows because they are formed by visible light. Visible light includes all the wavelengths of light that the human eye can detect. It allows us to see objects in the world around us. Without visible light, we would only be able to sense most objects by sound or touch, and we would never see rainbows. Like humans, most other organisms also depend on visible light, either directly or indirectly. Many animals use it to see. All plants use it to make food in the process of photosynthesis. Without the food made by plants, most other organisms could not survive. Answer: visible light

Ex Output:

What helps us see rainbows in the sky?


