Liver's dual blood supply

Steps:

• Recall liver receives oxygenated blood via hepatic artery from aorta.
• Note portal vein delivers nutrient-rich blood from intestines to liver.
• Identify hepatic vein carries processed blood away from liver to vena cava.
• Confirm vena cava transports blood from liver toward heart, not to it.

Why A is correct:

• Hepatic artery and portal vein provide the liver's dual blood supply, as defined in human anatomy.

Why the others are wrong:

• B incorrectly excludes hepatic artery and includes vena cava, which drains from liver.
• C wrongly attributes inflow to hepatic vein and vena cava, ignoring artery and portal roles.
• D repeats C's errors, misidentifying outflow vessels as inflows.

Final answer: A