In this task, you are given a sentence and a question, you would be asked to create the answer which is contained in the sentence provided.
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Question: Sentence: There are four classes of biochemical compounds. Question: How many classes of biochemical compounds are there?

Answer: four


Question: Sentence: Test wells are drilled to monitor groundwater pollution. Question: What are drilled to monitor groundwater pollution?

Answer: test wells


Question: Sentence: Gravity causes rocks to roll downhill. Question: Which force causes rocks to roll downhill?

Answer:
gravity