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: Experiments are often done in a lab.
experiment lab.

Fact: Fish have a centralized nervous system with a brain.
brain allows thinking.

Fact: Cells secrete acids and bases to maintain the proper pH for enzymes to work.

ACIDS AND BASES.