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: Prokaryotes are single-celled organisms that lack a nucleus.
[EX A]: Prokaryotes.

[EX Q]: Fact: crumple means change shape from smooth into compacted by physical force.
[EX A]: compacted density.

[EX Q]: Fact: Air pollution harms the respiratory and circulatory systems.
[EX A]:
Air pollution caused by.