Final answer:
The hepatic portal system drains nutrient-rich blood from the alimentary canal, processing these nutrients and toxins at the liver before returning the blood to the heart.
Step-by-step explanation:
The hepatic portal system is responsible for draining nutrient-rich blood from various organs and delivering it to the liver. The correct answer to which part of the body the hepatic portal system drains nutrient-rich blood from is B. The alimentary canal. This includes organs like the stomach, intestines, and spleen. The liver receives this blood, which is rich in nutrients absorbed from the alimentary canal. It processes these nutrients, stores some for later use, removes toxins and sends the cleaned blood back to the heart via the inferior vena cava. The gall bladder's cystic veins, the pancreas, and other organs also contribute to this system, but it is the alimentary canal that is primarily drained by it.