Which of the following exhibits female heterogamety?

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

$A$: Holandric traits are passed from one generation to the next generation.
$R$: These traits appear more frequently in one sex than in other.

In humans,sex-linked traits are primarily transmitted by:

Assertion : In humans,the gamete contributed by the male determines whether the child produced will be male or female.
Reason : Sex in humans is a polygenic trait depending upon a cumulative effect of some genes on $X-$ chromosome and some on $Y-$ chromosome.

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