Question: Where does the umbilical vein enter the circulation of the fetus?
Disambiguated questions and answers: question: Where does less than a third of the blood from the umbilical vein enter the circulation of the fetus?
Where does more than two thirds of the blood from the umbilical vein enter the circulation of the fetus?
answer: Ductus venosus
ductus venosus and is carried to the inferior vena cava
enters the liver proper from the inferior border of the liver
portal vein
Natural Questions answer: the portal vein (from the Wikipedia article "Fetal circulation")