The Opossum in North America. Nearly 250 other species in New Guinea, Tasmania, and Australia . Placental mammals, the Eutherians Viviparous mammals, giving birth to well developed young that have been nourished by a placenta in the uterus of the female. Every mammal native to the United States is a placental mammal, except the Opossum. The period between fertilization and birth.
Mammal teeth are highly specialized.
Examining the teeth can tell you a lot about the habits of the animal. Pulp cavity - contains blood vessels and nerves. Root canal - the canal through which blood vessels and nerves reach the body. The crown of a tooth is located above the gum. The root of a tooth is located below the gum.