The fetal circulatory shunt that allows oxygenated blood from the umbilical vein to largely bypass the immature liver is the:

1. The fetal cardiovascular system includes three key shunts that bypass immature organs. 2. Oxygenated blood arrives from the placenta through the umbilical vein. 3. One specific shunt allows this blood to bypass the immature liver almost entirely, delivering just a trickle to it. 4. Foramen ovale and Ductus arteriosus are both different figures a reader might guess from memory, but neither matches the specific figure given here. 5. Umbilical artery is also incorrect for the same reason: it does not match the specific figure given here. 6. This shunt is called the ductus venosus, distinct from the foramen ovale (which bypasses the lungs at the atrial level) and the ductus arteriosus (which bypasses the lungs at the arterial level). _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 28 "Development and Inheritance", p.1338-1339 §The Fetal Circulatory System_