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.

Input: Consider Input: Fact: Plants use cellulose for their cell walls.

Output: cell walls.


Input: Consider Input: Fact: Absorption of nutrients occurs mainly in the small intestine.

Output: Absorption of nutrients.


Input: Consider Input: Fact: burning wood is used to produce heat.


Output: burning wood trees.