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.
Q: Fact: Scales protect fish from predators and parasites and reduce friction with the water.
A: 
Friction is the force resisting.