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 bacteriophages at any point in time results from .

Frequency-Dependent Selection

Explanation:

Frequency-dependent selection can be determined in a variety of ways, which are not different, yet all convey the feeling that the wellness of a phenotype or genotype changes with the phenotypic or genotypic structure of the population. Such determination can promptly keep up phenotypic variety and hereditary variety at a solitary locus. The support of polygenic variety with recurrence subordinate determination are to some degree more prohibitive than in the single locus caseUtilizing a recreation model, Mani et al. (1990) investigated the consolidated impact of change, balancing out ward choice, and recurrence subordinate determination on a hereditary framework in which there are n (≤12) loci, each with up to 32 alleles that demonstration additively, the i allele contributing an amount I to the genotypic variationHence, the right answer for the fill up the blanks is "Frequency-Dependent Selection"

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