Answer:
The correct answer would be -
If the type of food available changes, then the frequency of beak also changes because the beak of the bird suited to food will survive successfully.
Step-by-step explanation:
According to the theory of natural selection, an organism that is able to adapt according to the change in the environment, it helps in their survival and increases their number in the system.
It is given that the type of food available is changing, so it will lead to the change in the frequency of bird beaks in that particular area. So, if they adapt to survive under the changes in the available food type, otherwise not be able to survive and die.
So,
If the type of food available changes, then the frequency of beak also changes because the beak of the bird suited to food will survive successfully.