TASK DEFINITION: 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.
PROBLEM: Sentence: Streak is a more reliable trait or measure to identify minerals. Question: Which is a more reliable trait or measure to identify minerals?

SOLUTION: streak

PROBLEM: Sentence: The stem is the basic structure that holds plants upright, allowing plants to get the sunlight and air they need. Question: What is the basic structure that holds plants upright, allowing plants to get the sunlight and air they need?

SOLUTION: stem

PROBLEM: Sentence: All matter in the universe is composed of one or more unique pure substances called elements. Question: All matter in the universe is composed of one or more unique pure substances called what?

SOLUTION:
elements