Lesson 13 Review Questions Directions: Answer each of the following questions. 1. List five traits that are shared by all mammals, including the two traits that are used to define the mammal class. 2. Describe how mammals stay warm. 3. What is the function of sweating? 4. What are alveoli? What is their function? 5. What are the functions of the uterus and vagina in therian mammals? 6. What is the placenta? What is its role? 7. Where does a marsupial embryo develop? How is it nourished? 8. Describe eggs and egg laying in monotremes. 9. How does lactation differ in monotremes and therian mammals? 10. What were the synapsids? When were they most widespread? 11. Identify the therapsids. How were they related to mammals? 12. Outline the evolution of monotreme, marsupial, and placental mammals.