Evaluate how internal fertilization and viviparity have contributed to the evolutionary and diversity of mammals.

Internal fertilization ensures that gametes are protected from environmental hazards and desiccation, increasing the probability of successful fertilization. This also allows for more controlled conditions for the initial stages of embryonic development.

Viviparity, particularly with the development of a placenta in most mammals, offers several key benefits:

• Protection: The developing embryo/fetus is protected within the mother's body from predators, harsh environmental conditions, and temperature fluctuations.
• Constant Nourishment: The mother provides a continuous and stable supply of nutrients and oxygen, and efficiently removes waste products, allowing for prolonged and complex development.
• Advanced Development: This sustained internal development leads to the birth of more mature and developed offspring, which have a higher chance of survival compared to externally developing young or those born at a very altricial stage.
• Maternal Investment: It allows for greater maternal investment in the offspring's development, freeing the young from the need to find food or regulate their own temperature immediately after conception.

These adaptations collectively led to higher offspring survival rates, enabling mammals to colonize diverse environments and evolve a wide array of specialized forms and behaviors, contributing significantly to their evolutionary radiation and the vast diversity observed today.