CBSE Class 12-science Answered

Every sexually reproducing species has two copies of each gene. These copies are called alleles. They are always responsible for contrasting characters. (EX – T for tallness and t for dwarfness)

Dominant alleles do not physically dominate the recessive allele. Whether the allele is dominant or recessive is decided based on the several experiments and their observations.

For example- after conducting the several crosses between tall pea plants and dwarf pea plants, the results indicated that whenever gene for tallness is present it is always get expressed irrespective of the presence of ‘t’ or when there is no ‘T’ gene present, ‘t’ shows its expression.