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: loud noises can cause animals to startle.
Example Output: animals mammal.

Example Input: Fact: when electricity flows to a light bulb , the light bulb will turn on.
Example Output: electricity electrons.

Example Input: Fact: Passive immunity lasts only as long as the antibodies survive in body fluids.
Example Output:
antibodies protein.