Which of the following statements is wrong regarding humans?

Which animal exhibits sex determination through the haplo-diploid mechanism?

Number of autosomal chromosomes in Drosophila.

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.

The person who discovered $Y$ chromosomes was

Which chromosomal condition is observed in male grasshoppers?