You are presented with the question "what can negatively impact a species?" and the following answer choices: 
- chemicals
 - elephant
 - cells
 - dog
 - drought
 - mines
 - steroids
 - amoeba

Now knowing that harming an animal species has a negative impact on the population size of that species and some species of amoeba are harmful parasites, choose the best answer.


 

        amoeba 