Final answer:
The umbilical cord contains three vessels: two umbilical arteries that carry oxygen-depleted blood to the placenta, and one umbilical vein that brings oxygen-rich blood to the fetus.
Step-by-step explanation:
The umbilical cord should contain three vessels: two arteries and one vein. The two umbilical arteries carry oxygen-depleted blood away from the fetus to the placenta. In contrast, the single umbilical vein carries oxygen-rich blood from the placenta to the fetal heart, providing essential oxygen and nutrients. It is important to note that blood does not go directly to the fetal lungs, as the fetus relies on the mother's oxygen supply.