Fact 1: Playing is one way mammals and other animals learn how to behave. Fact 2: Playing is really fun. Given the two facts above, what is one way mammals learn to behave?

pick from the following.
(A). sleeping
(B). motion
(C). sweating
(D). Having fun
(E). Movement
(F). magic
(G). during the day
(H). disease
Answer:
(D).