Generate a sentence that answers this question: "If a thing reacts in a situation, the most likely reason for the chemical reaction is".

Answer: adding heat to an object sometimes causes chemical reactions

Generate a sentence that answers this question: "an animal is controlled by a".

Answer: an animal 's brain controls that animal

Generate a sentence that answers this question: "A crane starts off weighing thirty pounds, then later weighs twenty pounds. When travelling, the crane will fly".

Answer:
as the weight of an animal decreases , that animal will fly more easily