Genetics is the study of inheritance.
The fact that the offspring of any species resemble the parents indicates that the characters in the parents are passed on to the offspring.
Factors that determine characters (genes) are passed on from parent to offspring through gametes or sex cells.
In fertilization the nucleus of the male gamete fuses with the nucleus of the female gamete.
The offspring show the characteristics of both the male and the female.
Genetics is the study of how this heritable material operates in individuals and their offspring.