On the Galápagos Islands, the finches that Darwin studied tended to have either small beaks or large beaks. The smaller beaks are best at eating soft seeds but are ineffective at cracking large seeds. The larger beaks are best at cracking hard seeds. Beaks of intermediate size are inefficient for either seed type. Which result of natural selection is at work in this example?

A. stabilizing selectionB. directional selectionC. disruptive selectionD. individual selectionE. unnatural selection

The correct answer is option C. "disruptive selection".

Explanation:

Disruptive selection is a type of natural selection at which extreme values for a trait are favored, while intermediate traits are more likely to disappear. In this example the finches tended to have either small beaks or large beaks because small beaks are best at eating soft seeds and large beaks are best at cracking seeds. This is an example of disruptive selection because the two extreme values for the size of beaks are favored.