You are presented with the question "What is a complex interaction shared by mammals and other animals?" and the following answer choices: 
- seeing
 - firm hugs
 - food
 - staring
 - power
 - blinking
 - sound
 - playing

Now knowing that playing is just one of many ways that mammals and other animals learn how to behave and people behave as a result of a complex interaction, choose the best answer.


 

        playing 