Refer to Infographic below. 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. Use the Infographic to identify and name which result of natural selection is at work in this example.

Disruptive selection

Explanation:

According to the infographic that is attached below showing different the three main types of selection that occurs as a result of natural selection taking its course on any population, we can draw our conclusion regarding the information given to us from the question.

From the question above, it states that the finches studied by Darwin are majorly finches with either small beak or large beak which are all adapted to suit the type of food available for the finches in the islands. Whereas, finches with intermediate beaks are favored against.

According to the infographic, disruptive selection can be said to have taken place as extreme traits are favored against intermediate traits on the islands.

"do a testcross with a homozygous recessive plant."