Given a fact, create a question that can be answered using the fact. Construct the question such that it is unambiguous, has a unique answer and the answer can be given using the fact.

[EX Q]: Fact: In the food chain process a green plant has the role of producer
[EX A]: Plants are called producers because they may produce their own?

[EX Q]: Fact: milliliters mL is a unit used for measuring volume generally used for values between 1 and 1000
[EX A]: Millilters mL is a unit generally used for values between 1 and 1000 to measure?

[EX Q]: Fact: biofuel is used to produce electricity by burning
[EX A]:
An example of biofuel could be?