During the drought of 1977, 84 percent of the medium ground finch population on daphne major disappeared. the individuals that survived had beaks that were deeper and larger than the beaks of individuals who did not survive.
given that natural selection favored large individuals with deeper and larger beaks, how can the presence of individuals with small, pointier beaks in 1983 be explained?
a) researchers were not measuring juvenile birds in 1977 but did measure juvenile birds in 1983. it is a well-known fact that juvenile birds are small and have small beaks.
b) these islands were colonized from the mainland. these small-beaked individuals must have flown over from ecuador.
c) even though the majority of birds after 1977 had deeper and larger beaks, there was still variation in beak size in the population. as seed type and seed availability changed, birds with beaks suited to exploit abundant seeds had higher reproductive success.
d) these islands must have received immigrants from a neighboring island.

Proteins are the workhorses of the cell, controlling virtually every reaction within as well as providing structure and serving as signals to other cells. proteins are long chains of  amino acids  , and the exact sequence of the amino acids determines the final structure and function of the protein. instructions for that sequence are encoded in  genes  . to make a particular protein, a messenger ribonucleic acid (mrna) copy is made from the gene (in the process called  transcription  ), and the mrna is transported to the  ribosome  . protein synthesis, also called  translation  , begins when the two ribosomal subunits link onto the mrna. this step, called initiation, is followed by elongation, in which successive amino acids are added to the growing chain, brought in by transfer rnas (trnas). in this step, the ribosome reads the  nucleotides  of mrna three by three, in units called  codons  , and matches each to three nucleotides on the trna, called the anticodon. finally, during termination, the ribosome unbinds from the mrna, and the  amino acid  chain goes on to be processed and folded to make the final, functional protein