Final answer:
The second stage of labor begins with complete dilatation of the cervix and ends with delivery of the baby. The third stage of labor is completed with the delivery of the placenta.
Step-by-step explanation:
The second stage of labor begins with complete dilatation of the cervix and ends with delivery of the baby. During this stage, the mother begins to push and the baby's head crowns as it passes through the birth canal. Once the baby is delivered, the second stage is completed.
In the third stage of labor, the placenta is delivered after the baby has been born.