Answer:
A place where plants and animals interact with each other and the physical environment.
If too many plant eaters were alive there wouldn't be any more plants so other animals eat the plant eaters, but if there is too many animals to eat the animals that eat the plants there would be too many plants so there is another animal to balance it out.
Hope this helps. 
Explanation:
 
        
             
        
        
        
<span>The overall amount of water on our planet has remained about the same for two billion years.
True.</span>
        
             
        
        
        
Answer:
Genetic engineering has been applied in numerous fields including research, medicine, industrial biotechnology and agriculture. In research GMOs are used to study gene function and expression through loss of function, gain of function, tracking and expression experiments.
Explanation:
 
        
                    
             
        
        
        
Answer:
d. consumer
Explanation:
Zebra and Deer are consumer (to be specific they are primary consumers) because they feed on plants only. Producers are organisms that create the food such as plants.