Hepatic portal system starts from 

Separation of oxygenated and deoxygenated blood.

I. Fulfils energy requirement of the body.

II. Ensures the effect transfer of oxygen in the body.

Oxygen rich blood from lungs comes to which chamber of the heart-

Figure below reflects the blood circulation system in the human body. Which of the path contains oxygenated blood.

The following statements about blood vessels is/are correct.

(A) Arteries have thin and less muscular walls

(B) Walls of veins are non-elastic

(C) Arteries have no valves in their inner lining

(D) Veins do not collapse when empty