Final answer:
The placenta plays a crucial role in transferring oxygen and nutrients from the maternal blood to the fetus, while also allowing fetal waste products to be removed via the umbilical arteries.
Step-by-step explanation:
Because the concentration of oxygen and nutrients is high in the maternal blood and low in the fetal blood, these substances move from the mother's blood through the artery walls and are carried to the fetus. The placenta, a unique circulatory organ that develops during pregnancy, facilitates this process. Maternal blood, carrying oxygen and nutrients, diffuses into the chorionic villi capillaries within the placenta and then transfers these vital substances into the fetal bloodstream. On the return trip, deoxygenated blood carrying fetal waste products moves from the fetus to the mother via the two umbilical arteries.