Write any three differences between arteries and veins.

ARTERIES	VEINS
Arteries are the blood vessels which carry oxygen-rich blood from the heart to all parts of the body.	Veins are the blood vessels which carry carbon dioxide-rich blood from all parts of the body back to the heart.
The arteries have thick elastic walls.	The veins have thin walls.
They do not have valves.	There are valves present in veins which prevent the backflow of blood.