(a) Mention any t

(a) The two components of blood are:

•Plasma

•Red blood cells

(b) The movement of oxygenated blood in the body can be depicted by the following flow chart:

Lungs → Left part of the heart → aorta → various organs

•The deoxygenated blood enters the heart through veins. The deoxygenated blood reached the lungs where it gets oxygenated.

•The oxygenated blood leaves the lungs via the pulmonary vein and returns to the left side of the heart.

•The blood then enters the left atrium, gets pumps through the mitral valve and then into the left ventricle.

•The left ventricle pumps the oxygenated blood to the different organs and body parts.

(c) The valves present between the atria and ventricles of the heart prevent the blood from flowing back when a contraction takes place.

(d) Arteries have thick elastic walls while veins are thin walled.

OR

(a) Excretion is the biological process of removal of toxic waste generated by the body. The waste produced is in form of excess water, salts, urea, uric acid etc.

(b) Nephrons are the basis filtration unit of the kidney. Each nephron includes a filter, called the glomerulus, and a tubule.

(c) (i) urine is formed by kidneys.

(ii) urine collection tube: Ureter

(iii) Stores urine: Urinary bladder