Variation in gene frequencies within populations can occur by chance rather than by natural selection. This is referred to as
Or
Random unidirectional change in allele frequencies that occur by chance in all population and especially in small populations is known as

Options

A. genetic flow
B. genetic drift
C. random mating
D. genetic load

Answer

B

Explanation

Genetic drift is a random change in allele frequencies over the generations. It is brought by chance alone. Gene flow or gene migration is the physical movement of alleles into and out of a population