The diagram shows part of the human circulatory system. Which structure is the hepatic vein?
▶️ Answer/Explanation
Ans: D
The hepatic vein carries deoxygenated blood away from the liver and back to the heart. In the diagram, it is labeled as D, distinguishing it from the hepatic portal vein (A), which brings blood to the liver, and other vessels like the vena cava (B) or arteries (C).
Key identifiers: The hepatic vein is not part of the portal system (A) and does not connect directly to the heart’s main veins (B). Thus, the correct answer is D.
The diagram shows the circulatory system of a fish.
What is the structure labelled X?
A) aorta
B) gills
C) heart
D) vena cava
▶️ Answer/Explanation
Ans: B
In fish circulation, blood becomes oxygenated at the gills (B). The heart (C) pumps deoxygenated blood, while aorta (A) and vena cava (D) are mammalian structures. X shows where blood changes from deoxygenated to oxygenated, indicating gills.