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: Introns are regions that do not code for proteins.
[EX A]: introns DNA.

[EX Q]: Fact: matter vibrating can cause sound.
[EX A]: cause sound.

[EX Q]: Fact: Plants are multicellular eukaryotes with cell walls made of cellulose.
[EX A]:
cell walls cellulose.