Inheritance of skin colour in human is an example of
Chromosomal aberration
Codominance
Point mutation
Polygenic inheritance
The hybrids are generally found to be superior to their parents, it is because of
Select incorrect one (w.r.t. reciprocal cross)
The first definite proof of mutagenic action of $X$-rays was given by
The phenotypic ratio obtained in quantitative inheritance of a dihybrid cross is