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.

[Q]: Fact: telephones are used for communication by two people by transmitting sound.
[A]: Sound is waves.


[Q]: Fact: Evolution is a change in the characteristics of living things over time.
[A]: Evolution.


[Q]: Fact: Insects may live in large colonies and have complex social behaviors.
[A]:
insect arthropod.