: It also produces hormones necessary to maintain the pregnancy and support fetal development. 2. The Strategy: Quality Over Speed

: It allows for the exchange of oxygen, nutrients, and water from the mother to the fetus, while whisking away waste like carbon dioxide.

: Humans, monkeys , and apes , known for large brains and grasping limbs. Carnivores : Predators like , and seals with specialized teeth. Cetaceans : Aquatic masters like whales and dolphins .

Placental mammals are mind-bogglingly diverse, categorized largely by how they move and eat.