An accidental change in DNA is a
Mutation or Speciation

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.

on island x the species needed to adapt because they were being subject to predators which didn't inhabit island y.  

answer; (b) clear with a slight blue tint;

because it travels in smaller waves then all other colors, causing it to be the most visible color