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: Viruses are so small that they can be seen only with an electron microscope.
Example Output: electron microscope lens.

Example Input: Fact: All animals are heterotrophs.
Example Output: All animals are heterotrophs.

Example Input: Fact: the force of water against the seed coat causes a root to emerge from a seed.
Example Output:
a root to emerge from a seed.