What mammal nourishes its unborn offspring through a placenta inside its uterus?

The mammal that nourishes its unborn offspring through a placenta inside its uterus is called a placental mammal. This group includes most mammals, such as humans, elephants, and whales. The placenta facilitates the transfer of nutrients and oxygen from the mother to the developing fetus while also removing waste products. This reproductive strategy allows for longer gestation periods and more developed young at birth.