Where would you find haploid cells?

• A. In an animal's intestinal lining
• B. In the early embryo at the blastocyst stage
• C. In brain tissue
• D. In the gonads

Answer: (D)

Haploid cells carry a single set of chromosomes. They are produced in the gonads through meiosis to form gametes (sperm and eggs), each with one chromosome from every pair. This is essential so that fertilization can restore the diploid number when the sperm and egg join. In contrast, tissues like the intestinal lining and brain are made up of somatic (diploid) cells, and an embryo at the blastocyst stage is also composed of diploid cells derived from fertilization. So haploid cells are found in the gonads.