• Spermatogonia (diploid cells) undergo mitosis to produce primary spermatocytes. 1 mark
• Primary spermatocytes undergo meiosis I to form haploid secondary spermatocytes. 1 mark
• Secondary spermatocytes undergo meiosis II to form spermatids. 1 mark
• Spermatids differentiate into mature sperm cells (spermatozoa). 1 mark
• Sertoli cells provide nutrients and structural support for developing sperm. 1 mark
• Spermatogenesis occurs in the seminiferous tubules of the testis. 1 mark
• Testosterone stimulates sperm production in the testes. 1 mark

Award a maximum of 5 marks.

Similarities:

• Both involve mitosis to produce precursor cells. 1 mark
• Both involve meiosis to produce haploid gametes. 1 mark
• Both involve cell differentiation to produce mature gametes. 1 mark Differences:
• Spermatogenesis produces four haploid sperm per meiosis, while oogenesis produces one haploid ovum and three polar bodies. 1 mark
• Spermatogenesis is continuous from puberty onwards, while oogenesis has long pauses (e.g., meiosis I starts before birth, meiosis II completes only at fertilization). 1 mark
• Spermatogenesis occurs in the testes, while oogenesis occurs in the ovaries. 1 mark
• Millions of sperm are produced daily, whereas only one egg is released per menstrual cycle. 1 mark

Award a maximum of 6 marks: 3 marks for discussing similarities, and 3 marks for discussing differences

• The placenta facilitates the exchange of nutrients (e.g., glucose, amino acids) from the mother's blood to the fetus. 1 mark
• It allows for the exchange of waste products (e.g., carbon dioxide and urea) from the fetus to the mother. 1 mark
• The placenta produces hormones, including human chorionic gonadotropin (hCG), which maintains the corpus luteum and progesterone production. 1 mark
• Later in pregnancy, the placenta secretes progesterone and estrogen to maintain the uterine lining and prevent contractions. 1 mark
• It acts as a barrier to some pathogens (though not all, e.g., some viruses like rubella can cross the placenta). 1 mark
• It provides oxygen to the fetus via diffusion. 1 mark
• It has chorionic villi to increase surface area for efficient exchange of substances. 1 mark
• The placenta prevents maternal and fetal blood from mixing, which is important due to possible differences in blood types. 1 mark
• The umbilical cord connects the fetus to the placenta, containing two arteries and one vein to facilitate blood transport. 1 mark

Award a maximum of 8 marks.