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: Plants use cellulose for their cell walls.
cell walls.

Fact: if an object is kicked then force is exerted on that object.
exerting force requires energy.

Fact: Blood pressure is highest in arteries and lowest in veins.

Blood pressure is.