They have a four chambered heart, and are endothermic, or warm-blooded. They have one-way lungs to get more oxygen. Birds have good vision, sense of smell and have a magnetic field detection. Lastly, class mammalia is what humans belong to. They have a four chambered heart, two way lungs, hair made of keratin, mammary glands, a diaphragm, teeth, endocrine system and are endothermic.
Placental mammals give birth to live young, and house the embryo until it is complete.
They have a placenta as a way of exchanging nutrients during development. This group includes most mammals, including humans. Marsupials give birth to premature young which make their way to a pouch made of hair and skin of their mother where they continue to develop. This group include kangaroos and other mammals like them. The monotremes are egglaying, and only include platypuses and the spiny anteater.