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: uneven heating of the Earth 's surface cause wind.
[EX A]: heating is warming.

[EX Q]: Fact: an animal requires energy to move.
[EX A]: animal energy from.

[EX Q]: Fact: Behaviors that improve fitness increase through natural selection.
[EX A]:
animal fitness.