Generate a sentence that answers this question: "What is larger then the human planet and causes cycles of day and night?".

Answer: the sun rising and setting causes cycles of day and night

Generate a sentence that answers this question: "Which of these is a source of heat?".

Answer: a hot substance is a source of heat

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