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: A solution forms when a solute dissolves in a solvent. Question: What forms when a solute dissolves in a solvent?
solution

Sentence: Mutation is essential in order for evolution to occur because it increases genetic variation and the potential for individuals to differ. Question: What phenomenon is essential in order for evolution to occur because it increases genetic variation and the potential for individuals to differ?
mutation

Sentence: Fresh water biomes are defined by low salt concentration. Question: What are fresh water biomes defined by?
low salt concentration