Given below is a diagram of a smear of human blood. Study the same and answer the question that follows:

(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)

1. Red Blood Cell (RBC),
2. White Blood Cell (WBC),
3. Blood Platelet
4. Blood Plasma.

(b) The red blood cells are minute biconcave disc-like structures whereas the white blood cells are amoeboid.

(c)The function of part 1 (RBC): Transport of respiratory gases to the tissues and from the tissues.
The function of part 2 (WBC): WBC plays a major role in defence mechanism and immunity of the body.
The function of part 3 (Blood Platelet): Blood platelets are the initiator of blood clotting.

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

(e) Thromboplastin