Given a scientific question, generate a correct answer to it.

Input: Consider Input: What is a compound that can form ions when it dissolves in water called?

Output: electrolyte

Input: Consider Input: Meters, such as those in analog fuel gauges on a car, are a common application of magnetic torque on a current-carrying what?

Output: loop

Input: Consider Input: Darwin coined what term to refer to an organism's relative ability to survive and produce fertile offspring?
Output: fitness