In your own words, explain why human sex cells only need 23 chromosomes.

during the gamete formation, both the male and female gamete are haploid to fuse and form a diploid zygote

Explanation:

the male gamete is the sperm and the female gamete is the egg. A normal human being has 46 chromosomes and have 23 pair of chromosomes. During fertilization the chromosomes are divided or halved i. e they are haploid. The male gamete gets 23 chromosomes and the female gamete gets 23 chromosomes. During the fertilization the male and female gamete join and form a diploid zygote that has 46 chromosomes.

It has 23 chromosomes because the male sperm has 23 and the female egg has 23. When they combine they make 46 chromosomes, the amount of chromosomes in the human body.