Genes that are similar in phenotypic effect when present separately,but together interact to produce a different trait and the ratio is $9:7$ in the $F_2$ generation. What are such genes known as?

Milk secretion and beard growth,both the traits are

What is $HbA_2$ composed of?

Which of the following statements are incorrect? $(i)$ $ABO$ blood grouping is controlled by gene $I$. (ii) Gene $I$ has four alleles. (iii) $I^A$ and $I^B$ produce the same type of sugar. (iv) $I$ or $i$ produces a different type of sugar. $(v)$ $I^A$ and $I^B$ are incompletely dominant.

The inheritance of $ABO$ blood group is an example of which of the following conditions?
$I -$ Complete dominance,$\quad II -$ Co-dominance
$III -$ Multiple allelism,$\quad IV -$ Incomplete dominance

$A$ human male is heterozygous for autosomal genes $A, B$, and $G$, and also for the hemophilic gene $h$. What is the probability of his sperm being $abgh$?