Which statement about the beak size of finches on the island of Daphne Major during prolonged drought is true? Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted. The frequency of the strong-beak alleles increased in each bird as the drought persisted. Each bird evolved a deeper, stronger beak as the drought persisted. Each bird that survived the drought produced only offspring with deeper, stronger beaks than seen in the previous generation.

The correct answer is: Each bird's survival was strongly influenced by the depth and strength of its beak as the drought persisted.

Grant is a scientist who did his research on finches on the small island of Daphne Major, because the major factor influencing survival of the finches is the weather (there are only few predators or competitors on the island).

The big drought that occurred on the island, affected the survival of finches: the birds with smaller beaks they died of starvation while those with larger beaks could take advantage of alternate food sources because they could eat larger seeds with their larger beak. After two years, Grant found that the beaks of the offspring became larger than their grandparents and that was the evidence that natural selection took place.