I have to say airborne infections. If the infection is airborne it can travel and infect many people more quickly and wide spread.
Answer:
Natural selection causes change in allele frequencies within a population.
So option A is correct one.
Explanation:
Natural selection generally work on an organism’s phenotype, or observable features. Phenotype is often largely a product of genotype (the alleles, or gene versions, the organism carries). When a phenotype produced by certain alleles helps organisms survive and reproduce better than their peers, natural selection can increase the frequency of the helpful alleles from one generation to the next – that is, it can cause microevolution.
Sugar is needed for scientists to grow plants
