Heterosome is called

In humans,sex determination is controlled by which of the following?

In our society,women are often blamed for producing female children. Choose the correct answer regarding sex determination in humans.

$A$: $XO$ type sex determination is found in a large number of insects.
$R$: Some of the sperms bear the $X$-chromosome,whereas some do not.

The sex of a human child is determined by:

$A$ fruit fly is heterozygous for sex-linked genes and is mated with a normal female fruit fly. In what proportion will the male-specific chromosomes enter the egg cells (in $:1$)?