When can genetic drift occur?
A
It can occur in small populations when alleles increase or decrease by chance over time.
B
It can occur in large populations when alleles increase or decrease by chance over time.
C
It can occur in large populations when alleles increase or decrease as a result of natural selection over time.
D
It can occur in small populations when alleles increase or decrease as a result of natural selection over time.

Respuesta :

Genetic drift describes random fluctuations in the numbers of gene variants in a population. Genetic drift takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time. These variations in the presence of alleles are measured as changes in allele frequencies.