A. Describe the key features of the mammalian reproductive system, including internal fertilization and viviparity .

a) The mammalian reproductive system is characterized by two key features: internal fertilization and viviparity.

Internal fertilization is the process where the male gametes (sperm) are deposited directly into the female reproductive tract, allowing the fertilization of the egg to occur inside the female's body. This protects the delicate gametes from environmental hazards and increases the probability of successful fertilization.

Following internal fertilization, most mammals exhibit viviparity, meaning the embryo develops internally within the mother's uterus. The developing offspring receives continuous nourishment and protection directly from the mother, typically through a placenta, leading to a more advanced developmental stage at birth and significantly higher survival rates compared to external development.