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.

Sentence: It is dark does photosynthesis not occur in the deep-water zone. Question: Why does photosynthesis not occur in the deep-water zone?
it is dark

Sentence: Sexual reproduction, in general, relies on sets of cells that are precursors for eggs and sperm. Question: What kind of reproduction, in general, relies on sets of cells that are precursors for eggs and sperm?
sexual

Sentence: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract. Question: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what?

contract