Nearly flat. Rhinos don't really reproduce rapidly.
        
             
        
        
        
Hormones
The endocrine system includes various glands in the body that are responsible for secreting hormones into the bloodstream. Hormones are chemical substances produced by the body that regulate certain functions of cells and organs. Hormones can regulate sleep, sex, growth, stress, huger, metabolism, etc. 
        
             
        
        
        
"Can dogs identify colors?" is a question that can be answered scientifically. but "Are dog better than cats?" cannot be answered scientifically because it will be answered with personal opinion.