Zoology - Principles of Inheritance and Variation Question with Solution | TestHub

1) The male fruit fly has XY sex chromosomes and produces two types of gametes. Hence, it is called heterogametic.

2) The female grasshopper is XX and the male XX-XO systems produce gametes with (X) or without (O) a sex chromosome. Hence, in male grasshopper, 50% of sperms have no chromosome.

3) Birds have a ZW sex-determination system. The sex of the embryo is determined by the egg in birds and not by the sperm. However, it is written here that the sperm decides the sex of the progeny. 

4) In humans, the Y chromosome is considerably smaller than the X chromosome and has a much lower density of genes. In fact, the Y has often been called a genetic junkyard.