You are presented with the question "The average number of individuals per unit of area affect the balance of ." and the following answer choices: 
- gravity
 - the environment
 - energy
 - Earth orbiting the Sun
 - an organism's body
 - objects that have mass
 - competition
 - power

Now knowing that population density is the average number of individuals per unit of area or volume and population densities affect the balance of the environment, choose the best answer.


 

  the environment       