Heredity:
The transmission of characters from one generation to the next or from parents to offsprings is called heredity.
Variation:
The differences between parents and offsprings or among the offsprings of the same parents and among individuals of the same species is called variation.
Genetics:
It is a branch of biology which deals with the study of heredity and variations. The term ‘genetics’ was coined by William Bateson in 1906.