Placenta is the circular organ present in the uterus of pregnant mammals which is required for the nourishment and maintenance of the fetus.The placenta begins forming at the point of implantation, which is about 8 days after the point of conception.The three main functions of placenta are
1. Attach the fetus to the uterine wall.
2. Provide nutrients to the fetus.
3. Allow the fetus to transfer waste products to the mother's blood.