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: the Earth revolving around the Sun causes the seasons to change on its axis.
Example Output: earth axis.

Example Input: Fact: fog is formed by water vapor condensing in the air.
Example Output: fog is formed.

Example Input: Fact: Producers make food from inorganic molecules.
Example Output:
inorganic molecules.