The umbilical cord of a human fetus normally contains
- A. one artery and one vein
- B. two arteries and one vein
- C. two arteries and two veins
- D. one artery and two veins
Explanation
Two umbilical arteries carry deoxygenated blood and wastes from fetus to placenta, while the single umbilical vein returns oxygenated blood and nutrients. Veins here carry waste and arteries carry it away, the reverse of the adult pattern, which catches many students.