A normal zygote has 23 of what?

A normal zygote has 23 pairs of chromosomes, which are homologous.

Explanation:

Meiosis is the sexual reproduction method used, which has sex cells like sperm and eggs. This creates four daughter cells with half as many chromosomes.

With each of the gametes created by the process of meiosis, it will have one pair from each of the homologous chromosomes. When both of the gametes meet during the fertilization stage, the zygote will have 23 pairs of chromosomes.

While this is the normal amount a human has, things can happen that can mess up the cell division stage and add an extra chromosome.