Assertion: Darwin's finches are a classical example of natural selection.
Reason: Darwin explained that the difference in size and shape of the beaks of the species was a result ofthe adaptation ofthe species to different food habits.

If both assertion and reason are true and reason is the correct explanation of assertion.

If both assertion and reason are true but reason is not the correct explanation of assertion.

If assertion is true but reason is false.

If both assertion and reason are false.

Solution

If both assertion and reason are true and reason is the correct explanation of assertion.

Darwin's finches represent an excellent example of adaptive radiation. Darwin's finches showed wide variations in beak shape and size from island to island. Darwin deduced that these variations made the finches better adapted to take advantage of the food in their particular local environment - thin, sharp beaks prevailing where the birds' main food was insects and grubs, and large claw shaped beaks where their diet was buds, fruits and nuts.