Substances known as 'heredity carriers' are

The seven pairs of contrasting traits in pea plants studied by Mendel were actually located on how many chromosomes?

$A$: Mendel proposed postulates like "principles of segregation and principles of independent assortment" after studying seven pairs of contrasting traits in garden pea.
$R$: He was lucky in selecting seven characters in pea that were located on seven different chromosomes.

$A$ human male is heterozygous for autosomal genes '$A$' and '$B$'. He is also hemizygous for the haemophilic gene '$h$'. What percentage of sperms will carry the '$abh$' genotype (in $\%$) (in $\%$)?

$A$ test cross is important to determine the:

Change of male and female parents during crosses is known as