<span> "People are promoted into positions they are not qualified to perform" relate to - the Peter Principle. </span>
It can affect the environment a little because it is explaining what it can do over the time when the evolution grows
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Answer:
Difference in their beak size, colour of their feather and body size.
Explanation:
The genetic variation that occurs in the three different species of bird is the difference in their beak size, colour of their feather and body size. The difference of beak size occurs due to difference in their food selection that is available to the birds. Some birds of the population feed on small food particles having small beak size whereas other have large beak size due to preference of large food materials. Some birds have colour like their surrounding that helps them to hide from their predators. Some birds specie have large body size due to availability of more food or due to genetics.