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: hibernation is used for conserving energy by some animals.
Example Output: conserving energy helps animals survive.

Example Input: Fact: Active immunity results when an immune response to a pathogen produces memory cells.
Example Output: Active immunity.

Example Input: Fact: Sperm pass out of the body through the urethra.
Example Output:
Sperm ejaculate.