You are presented with the question "Ethologists study how animals use what in their natural environment" and the following answer choices: 
- Energy
 - Chlorophyll
 - fur
 - digestion
 - instincts
 - lungs
 - an object
 - Energy.

Now knowing that ethologists usually study how animals behave in their natural environment and animals behave according to instinct, choose the best answer.


 

     instincts    