You are presented with the question "What can teach animals how to behave?" and the following answer choices: 
- adding heat
 - humans
 - fossil fuels
 - A computer
 - nerves
 - people
 - irradiation
 - exercise

Now knowing that playing is one way mammals and other animals learn how to behave and exercise is fun if it is also play, choose the best answer.


 

        exercise 