In animals, which statement correctly describes chromosome sets in gametes and somatic cells?

• A. Gametes have two sets; somatic cells have one.
• B. Somatic cells have one set and gametes have two.
• C. Gametes have one set and somatic cells have two.
• D. Both have one set.

Answer: (C)

In animals, the number of chromosome sets differs between gametes and somatic cells. Gametes are haploid, meaning they contain a single complete set of chromosomes. Somatic cells are diploid, containing two complete sets—one from each parent. Meiosis produces the haploid gametes, and fertilization restores the diploid number when two gametes fuse to form a zygote. For humans, that means gametes have 23 chromosomes and somatic cells have 46, arranged as 23 homologous pairs. If somatic cells had only one set, chromosome number would drop with each division; if gametes had two sets, chromosome number would double after fertilization. Therefore, the correct description is that gametes have one set and somatic cells have two.