The number of autosomes in a human is (in $pairs$)

In the buccal cavity slide cell of an individual, we observe a dark-stained body near the nuclear membrane. The genotype of the individual may be

$A$ family has $9$ daughters. What is the probability of having a son at the $10$th birth (in $\%$)?

In humans,the chromosomal composition of a female-destined zygote is:

$A$ fruit fly is heterozygous for a sex-linked gene. It is crossed with a normal female fruit fly. The specific chromosome for the male enters the egg in the ratio of ............. (in $: 1$)

Which of the following conditions of gametes results in the birth of a normal human female child?