Given below is a diagram of a smear of human blood. Study 4 the same and answer the questions that follow:

(a) Name the parts 1, 2, 3 and 4 indicated by guidelines.

(b) Mention two structural differences between the parts labelled ' 1' and '2'.

(c) What is the main function of the parts labelled 1, 2 and 3 respectively ?

(d) What is the lifespan of the part labelled '1'?

(e) Name a soluble protein found in '4' which helps in the clotting of blood.

(a) From the diagram shown, the following parts are labelled as shown below:

1 : Red blood cells (as the part labelled as 1 is circular and biconcave)

2 : White blood cells (as the part labelled 2 is irregular in shape)

3 : Platelets

4 : Blood plasma

(b) Two structural differences are:

(c) The main functions are :

Part 1 (Red blood cells) - Absorbs and transfers oxygen to various parts of the body.

Part 2 (White blood cells) - Engulf particle like solid substances by phagocytosis and produces antibodies.

Part 3 (Platelets) - Initiators of clotting blood.

(d) The average life span of Red blood cells are about 120 days.

(e) The soluble protein found in the blood plasma which helps in the clotting of blood is fibrinogen or prothrombin. Prothrombin is a protein produced by our liver. It is a carbohydrates-protein compound. Prothrombin is transformed into thrombin by a clotting factor called factor X or prothrombinase.