TASK DEFINITION: In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.
PROBLEM: Question: What is a byproduct from the combustion of fossil fuels like coal and gasoline? Answer: nitrogen dioxide

SOLUTION: Nitrogen dioxide is a byproduct from the combustion of fossil fuels like coal and gasoline.

PROBLEM: Question: Lipids are available to the body from how many sources? Answer: three

SOLUTION: Lipids are available to the body from three sources.

PROBLEM: Question: What is the name of the location in which a stream or river starts? Answer: source

SOLUTION:
Source is the name of the location in which a stream or river starts.