Placental mammals, such as humans, dogs, and cats, develop embryos inside a uterus. The embryos are nourished and protected by a specialized structure called the placenta, which develops in the mother's uterus during pregnancy. The placenta allows the exchange of nutrients and waste products between the mother and the developing fetus through the umbilical cord. This is how the fetus receives oxygen and nutrients while eliminating waste products. The development of placental mammals is a complex process that involves various stages, including fertilization, embryonic development, and the eventual birth of live young.
