1.	Due to presence of ______ , back flow of blood is prevented in veins.
	Septa   Valves   All of these   Thick walls
2.	Very fine vessels called capillaries connect arteries and veins to each other.
	True   False
3.	Which of the following is true?
	Platelets contain single nucleus.   Platelets contain an ill-defined nucleus.   Platelets contain many nuclei.   Platelets do not contain nucleus.
Hint Dica
4.	Identify the blood vessel ‘A’ in this diagram.
	Inferior vena cava   Aorta   Carotid artery   Pulmonary artery
5.	Which blood vessels carry blood from heart to various parts of the body?
	Veins   All of these   Capillaries   Arteries