A woman has an $X$-linked condition on one of her $X$ chromosomes. This chromosomes can be inherited by

Sex determination in Drosophila melanogaster is based on

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.

$X$ -chromosome or $X$ - body was first observed by.............

Select the incorrect statement

Which one of the following conditions correctly describes the manner of determining the sex?