Question

After which event could you say that evolution has occurred?

Answer 1

 C, because alleles are alternative forms of a gene that arise from mutation.

Answer 2

Answer:

C. An allele frequency changes in a population

Explanation:

Evolution refers to the accumulation of genetic variations in the gene pool of population leading to the origin of the better adapted population. Evolutionary agents such as mutations, natural selection, gene flow, etc. change the allele frequency in the gene pool of the population.  

The changed allele frequency of a population represents that fact that one or more of the above mentioned evolutionary agents are working on the gene pool and population has occurred.