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.

Example Input: Sentence: Test wells are drilled to monitor groundwater pollution. Question: What are drilled to monitor groundwater pollution?
Example Output: test wells

Example Input: Sentence: Natural selection works by selecting for alleles that confer beneficial traits or behaviors, while selecting against those for deleterious qualities. Question: What works by selecting for alleles that confer beneficial traits or behaviors, while selecting against those for deleterious qualities?
Example Output: natural selection

Example Input: Sentence: Lithium has three electrons. Question: How many electrons does lithium have?
Example Output:
three