In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer?

A. The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein.

B. The resistant corn borers must survive better or reproduce more than non-resistant corn borers.

C. The corn borers must experience unlimited success in their ability to survive or reproduce.

D. The corn borers must experience no success in their ability to survive or reproduce.

E. The corn borer must lack variation in resistance to the toxic protein.

a. The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein.

b. The resistant corn borers must survive better or reproduce more than nonresistant corn borers.

Explanation:

When there is a change in the surroundings of organisms, some genetic variations become beneficial to the organisms. Natural selection favors the organisms having these genetic variations.

The development of resistance in the corn borer population requires the presence of the gene for the resistance in the population. If there is no gene already present in the population, there should be a mutation to give rise to such gene/s. The corn borers having this gene should be able to survive better in the presence of the toxic protein and should leave more progeny in order to increase the frequency of the gene in the population over the generations.