Charles Darwin made famous observations of finches on islands in the Pacific Ocean. The birds were believed to have come all from one population, but when separated on the islands with different habitats, the birds changed. The beaks of the birds on islands with lots of seeds were different from the beaks of the birds on islands with lots of insects. How did their beaks come to match the food in their environments so well

Evolution

Explanation: The birds where able to adapt to their new environment by developing beaks that could help them in feeding easily on their various food sources. The change may not have occured at once, but through a gradual process of evolution and inheritance. Gradually the beak changes as they try to get used to the various feeding methods in their respective environments.

Simply birds with the right beak shapes for insects and seeds will be naturally selected , and therefore have more population than those with wrong beak shapes.

Explanation:

This detailed the concept of variation, which lead to natural selection against selective pressure,  for   birds with adaptable beaks for survival.

Since the birds were originally  of the same population. Definitely it was the selection pressure(feed types) in their different  new environments, that made them to developed different beak size in order to adapt to  survive .

In insect dominated environment, birds which populated the habitat  must have developed certain  traits for this through variation, and those which lack the gene for the beak shape were selected out from the population.Hence, birds with right beak shape  for insect will survive, and have more young than the less fitted one.

Likewise, in seed dominated environment, only birds  with right beak shape for picking the seeds will dominate the population, because they are well adapted against the selective pressure ,they are  the  survival of the fittest, and are therefore naturally selected ahead of those with wrong beak.Their young will therefore dominate the population.

i think the answer would d