A sudden or spontaneous change in the structure and action of a particular gene is called:
Mutation
The correct option is B:
Explanation of the correct option:
A sudden change in the structure and action of a particular gene is called a mutation.
Explanation of the incorrect options:
Option A:
The tendency of the genes on the same chromosome to stay together in the hereditary transmission is known as linkage.
Option C:
Variation is any difference between cells, individual organisms, or groups of organisms.
Option D:
Allelomorph is an alternative form of a gene that is present at the same locus on a specific chromosome and that control the same character.
Final answer: A sudden change in the structure and action of a particular gene is called a mutation.