Explain why gametes need half the chromosomes of somatic cells?

Gametes undergo meiosis, which means they split into four haploid cells with 23 chromosomes each. This is so when the gametes fuse the full number of chromosomes is reached, making 46 chromosomes

A somatic cell is a normal body cell which has 46 chromosomes. Gametes have 23 chromosomes because during fertilisation they fuse with the other gamete to get 46 chromosomes; which is the correct number of chromosomes a normal body cell should have. If gametes didn’t have 23 and had 46 chromosomes in the gamete the embryo will end up with 92 chromosomes and that’s not the number of chromosomes a normal somatic cell has.