The number of pair (s) of sex chromosomes in the zygote of humans is
(a) one (b) two
(c) three (d) four
The number of sex chromosomes in the zygote of humans is one pair. It is not always a perfect pair. In females, it is perfect with two X chromosomes. However, in males, there is one X chromosome and one Y chromosome.
Therefore, option (a) is correct.