instruction:
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.
question:
Fact: optical tools are used for observing materials up close.
answer:
materials.


question:
Fact: Amphibians are the first true tetrapods, or vertebrates with four limbs.
answer:
Amphibians.


question:
Fact: Cnidarians are invertebrates such as jellyfish and corals.
answer:

Cnidarians.