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 load
B. Genetic flow
C. Genetic drift
D. Random mating

Answer

C

Explanation

Genetic drift or Sewall Wright effect is an important mechanism in evolutionary change in small population. In a small population not all the alleles which are representative of that speciea may be present. Therefore, chance events may result in the elimination of that allele from population.