The population of the Atlantic puffin will decrease because of inability to obtain food.
What is mutation?
A mutation is an abnormal change that occurs in the sequence of nucleotides in a DNA molecules of an organism.
Assuming a mutation occurs in the beak of the Atlantic puffin that affects it ability to eat fish species A.
Since, species A is the most abundant fish species, the population of the Atlantic puffin will decrease because of inability to obtain food.
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