What are the genes that code for a pair of contrasting traits called?

$A$: Dominance is not an autonomous feature of a gene.
$R$: It depends as much on the gene product and the production of a particular phenotype from this product.

$A$ test cross in plants and Drosophila involves crossing between:

Describe test cross. Why is it necessary?

In pea plants,if the $Bb$ gene is present in a heterozygous condition for starch grain synthesis,what type of inheritance does the round seed shape exhibit?

How many types of gametes can be produced by an organism with the genotype $AABBCC$?