In this task, you need to write a topic word from the given fact. The topic word must have at least one word overlap with the given fact. The topic word often involves adding a new word from a related concept. In your topic word, use at least one word from the given fact. Topic words with two or more words work best.

[EX Q]: Fact: Muscle contraction occurs when muscle fibers get shorter.
[EX A]: Muscle contraction.

[EX Q]: Fact: if an object is made of a material then that object has the properties of that material.
[EX A]: Material is a substance.

[EX Q]: Fact: Roundworms make up the phylum Nematoda.
[EX A]:
Nematoda.