Question

Distinguish between monogenic & polygenic inheritance ...?

Answer 1

"Mono" means one, and "poly" means many, so monogenic would be once gene inheritance, and polygenic would be multiple gene inheritance.

Answer 2

Monogenic InheritanceTheir expression of trait produces discontinuous variation. The complete trait was expressed by a dominant allele. Qualitative traits are controlled by monogenic inheritance. Dominant parent and F1 individuals are similar.
Polygenic inheritanceContinuous variations in the expression of a trait are produced by polygenes.Unlike monogenic, just a single dominant allele expresses only a unit of the trait of a polygenic. Either quantita­tive or metric trait was controlled by polygenic inheritance. One to several pairs of alleles is representing a character.The dominant genes have increased effect on the expression of the trait. There is more intermediate form. Individuals with the dominant trait are usually as few like recessive trait.