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.
--------
Question: Sentence: Ions that contain fewer electrons than protons have a net positive charge and are called cations. Question: Ions that contain fewer electrons than protons have a net positive charge and are called what?

Answer: cations


Question: Sentence: Most ocean waves are caused by wind. Question: Most ocean waves are caused by what?

Answer: wind


Question: Sentence: A tracer is the name for a substance that can be used to follow the pathway of that substance through some structure. Question: What is the name for a substance that can be used to follow the pathway of that substance through some structure?

Answer:
tracer