Given below is a diagram of a smear of human blood. Study 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 life span of the part labeled "1"?

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

(a) The parts indicated are as follows —

• 1 → Red Blood Cell (RBC)
• 2 → White Blood Cell (WBC)
• 3 → Blood Platelet
• 4 → Blood Plasma

(b) Two structural differences between red blood cells and white blood cells are:

(c) The main functions of the parts labelled 1, 2 and 3 are as follows:

1. Part 1 (Red Blood Cell) — Transport of respiratory gases to the tissues and from the tissues, transport of nutrients from the alimentary canal to the tissues.
2. Part 2 (White Blood Cell) — WBCs play major role in defense mechanism and immunity of the body.
3. Part 3 (Blood Platelet) — Blood platelets are the initiators of blood clotting.

(d) The average life span of a red blood cell (RBC) is about 120 days.

(e) Fibrinogen.