Hi the answer is individuals. Hope this helps.
The digestive system enlists the aid of the cardiovascular system and the nervous system. Blood vessels of the digestive system widen to transport more blood.
Welp you have to show the model...
This is a positive mutation, because the offspring will survive longer to reproduce. Their offspring will then carry the same genes passing it off to their offspring. The other color mice that did not blend into its environment will soon be extinct, leaving only the mice that can blend in.
