(a) Arteries possess thick elastic wall without valves inside, blood flows under high pressure and carry blood away from the heart to different parts of the body.

(b) Thin walls of arteries have valves inside and blood flows with low pressure and carry it away from the heart to different organs.

(c) They possess thick elastic walls, blood flows under low pressure; carry blood from the heart to various various parts of the body.

(d) They possess thick elastic walls, blood flows under high pressure; collect blood from different organs and bring it back to the heart.