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: Most invertebrates have a nervous system.
Example Output: invertebrate.

Example Input: Fact: Bryophytes occupy niches in moist habitats.
Example Output: bryophytes.

Example Input: Fact: Hagfish are noted for secreting large amounts of thick, slimy mucus.
Example Output:
hagfish ancient.