Sex cells: sperm or eggs (ova).

• A. Somatic cells
• B. Gametes
• C. Endoplasmic reticulum
• D. Mitochondria

Answer: (B)

Sex cells are specialized reproductive cells that carry half the genetic material needed to form a new individual. In humans, these are sperm in males and eggs (ova) in females, collectively called gametes. They are haploid, containing one set of chromosomes, and are produced by meiosis so that fertilization by a gamete from the opposite sex restores the full diploid chromosome number in the offspring. The term gametes directly describes sex cells and their role in sexual reproduction.

Somatic cells are all the body’s non-reproductive cells and are diploid, not used as the reproductive gametes. The endoplasmic reticulum and mitochondria are organelles within cells that perform cellular functions like protein synthesis and energy production, not reproductive cells.