1. Due to presence of _______ , back flow of blood is prevented in veins.   Valves   Thick walls   Septa   Arteries   Hint Half-n-half Clue   2. Contraction of ventricles is known as diastole.   True   False   3. Normal blood pressure (BP) in a 25-year-old man is _______ mm Hg.   170/100   120/80   140/90   100/60   Half-n-half Clue   4. This statement is not true :   Left side of the heart contains oxygenated blood.   Pulmonary veins carry oxygenated blood.   Right ventricle pumps blood to various parts of the body.   Valves are present between auricles and ventricles to prevent backflow of blood.   Hint       5. Bleeding time is prolonged in hemophilia.   True   False   6. Which of these does not cause an increase in pulse rate?   Sleep   Exercise   Anxiety   Fever   Hint       7. This statement is not true :   Veins return blood from the various parts of the body to the heart.   All veins carry deoxygenated blood.   Veins are thin-walled.   Veins contain valves.   Hint