The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. The outcome of the conflict between bacteria and bacteriophage at any point in time results from .A) frequency-dependent selection.
B) heterozygote advantage.
C) stabilizing selection.
D) genetic variation being preserved by diploidy.
E) neutral variation.

Frequency dependent selection.

Explanation:

Frequency dependent selection can be defined as evolutionary process by which the fitness of the phenotype or genotype is dependent on the genotype or phenotype of the composition of the given population.

Frequency dependent selection is the result of the interaction between the species( parasitism, competition or predation)

It can also lead to the dynamical chaos when the fitness of the individual becomes very low.

answer: 20 percent

the fish culture has become a developing commercial practice in developing countries which is already prominent in developed countries of the world. the major fish protein demand is being supplemented in developing countries is   fishing to meet the needs of the growing population. therefore, in some developing nations, the percentage of animal protein from fish in the diet can be as high as 20 percent.