Select from the following.
[A]. reusing things
[B]. Riding a bike
[C]. adding heat
[D]. sound
[E]. Movement
[F]. exercise
[G]. Having fun
[H]. sweating
Given those answer options, answer the question: Fact 1: Playing is just one of many ways that mammals and other animals learn how to behave. Fact 2: Playing is really fun. Given the two facts above, how do mammals learn to behave?
A:
[G].