instruction:
Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.
question:
Question: What is solid water that forms when water vapor undergoes deposition? Answer: frost
answer:
Frost is solid water that forms when water vapor undergoes deposition.

question:
Question: What does rising air do when it reaches the top of the troposphere? Answer: cools
answer:
The rising air cools as it reaches the top of the troposphere. The air gets denser, so it sinks to the surface. The sinking, heavy air creates an area of high air pressure near the ground.

question:
Question: What is a byproduct from the combustion of fossil fuels like coal and gasoline? Answer: nitrogen dioxide
answer:
The brown color is from nitrogen dioxide gas. Nitrogen dioxide is a byproduct from the combustion of fossil fuels like coal and gasoline.