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.

Example Input: Fact: Veins generally carry deoxygenated blood.
Example Output: blood.

Example Input: Fact: Viruses often infect bacteria.
Example Output: bacteria define.

Example Input: Fact: forming coal requires decaying vegetation.
Example Output:
are vegetables.