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: telephones are used for communication by two people by transmitting sound.
Example Output: Sound is waves.

Example Input: Fact: Skin color is a polygenic trait.
Example Output: Skin color.

Example Input: Fact: if fossils of an animal or plant are found in a place then that animal or plant used to live in that place.
Example Output:
fossil dinosaur.