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.

Fact: a graduated cylinder is used to measure volume of a liquid.
a graduated cylinder is used to measure volume of a liquid.

Fact: skin is used for breathing air by frogs.
air oxygen.

Fact: eyes are used for seeing by animals by sensing light.

animal mammals.