All three would decrease the size of the population of the organism. If an organism suddenly has a new predator, the organism's population will decline and it is likely that the members of the prey's population would disperse in an attempt to survive. Disease would just kill off the population in general, maybe the organism's population would distribute itself differently in order to avoid catching the disease. Competition would decrease the amount of food, water, and/or land available to the organism's population causing it to decrease or change habitats in an attempt to find another food source
        
             
        
        
        
This answer should be correct 
The adaptation that viceroy butterflies use is successful because it is so well adapted for the environment that it has evolved in.The ability of this butterfly to adapt to it environment has helped it survive in long term.But because the viceroy has been so successful it might also have come to a coast
        
             
        
        
        
Producing a contraction that changes both the length and the shape of the cell