Question

In polygenic inheritance, a trait is controlled by two pairs of genes. Two individuals which are heterozygous for
both genes, crossed each other, such type of cross produces what phenotypic ratio ?
(1) 1:2:1
(2) 9.3.3:1
(3) 1:4:6:4:1
(4) 1:6::15:20:15:6:1

please with explanation​

Answer 1

Explanation:

9:3:3:1 because all are taken as different types of traits