What structure allows for the passage of deoxygenated blood and waste products from the fetus to the placenta?

The correct choice involves the two umbilical arteries, which play a crucial role in fetal circulation. These arteries are responsible for carrying deoxygenated blood and metabolic waste products from the fetus back to the placenta. This process is vital for removing waste materials that the fetus produces, as well as ensuring that the blood returns to the placenta for reoxygenation and nutrient exchange.

In a fetal circulatory system, the umbilical arteries branch off from the internal iliac arteries and travel through the umbilical cord to reach the placenta. Once there, they release the waste products into the maternal circulation through the placenta, allowing for detoxification and nutrient replenishment. Thus, the function of the umbilical arteries is essential for maintaining fetal health and supporting development throughout pregnancy.

The umbilical vein, on the other hand, carries oxygenated blood from the placenta to the fetus, while the ductus teres and ductus deferens are unrelated structures that do not facilitate the transfer of blood or waste in this context.