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, answer the question "How do mammals learn to behave?" with the following options: 
- reusing things
 - Riding a bike
 - adding heat
 - sound
 - Movement
 - exercise
 - Having fun
 - sweating


 

       Having fun  