In the Study of Finches' Beaks,the Biologists Peter and Rosemary

In the study of finches' beaks,the biologists Peter and Rosemary Grant found that ____.

A) Darwin had underestimated the power of natural selection
B) under drought conditions,more thick-than thin-beaked birds survived and reproduced
C) in only one generation,natural selection produced a better-adapted species
D) when heavy rains became common,birds with slender beaks flourished
E) All of the choices are correct.