Final answer:
The umbilical cord contains blood vessels that link the fetus to the mother.
Step-by-step explanation:
The umbilical cord contains blood vessels that link the fetus to the mother. It is a tube that consists of two arteries and a vein. Blood from the fetus enters the placenta through the umbilical arteries, exchanges gases and other substances with the mother's blood, and travels back to the fetus through the umbilical vein.