Explanation:
Monotremes are mammals but they lay eggs instead of giving birth to live young, like marsupials and placental mammals. Monotremes are similar to reptilia in having shoulder girdle and egg. Although they share some reptilian features, Monotremes possess all the major mammalian characteristics, like air breathing, endothermy (i.e., they are warmblooded), mammary glands, a furred body, a single bone in the lower jaw and three bones in the middle ear.