Write a correct answer to the given question based on its associated fact. Make sure that your answer is contained in the associated fact. Don't be creative and introduce any new word that is not mentioned in the associated fact! Remember that the associated fact has been rearranged to form the question. So, the correct answer words must lie within the associated fact. The correct answer can be a word, phrase, or even a sentence.

Fact: plants are sensitive to darkness. 
Question: What are plants sensitive to?
darkness.

Fact: Heat from the sun helps frog eggs survive and hatch into tadpoles. 
Question: What heats frog eggs so that they may hatch into tadpoles?
the sun.

Fact: Completing a circuit causes the fan's blades to turn. 
Question: Completing a circuit causes fan's blades to what?

turn.