Fact 1: Playing is one way mammals and other animals learn how to behave.

Fact 2: Dogs, of course, are mammals.

Given the two facts above, answer the question "Playing is one way what learns how to behave?" with the following options: 
- bacteria
 - Man
 - roaches
 - koalas
 - dogs
 - humans
 - toads
 - bears


 

     dogs    