Dear Student,
When a drop of blood is observed under a microscope, three types of blood were seen.
a) Red blood cells: These are bi-concave disc shaped and have no nucleus. Red blood cells were observed as pink coloured. The main function of RBC is to transport oxygen to the different parts of the body.
b) White blood cells: These were seen as blue/purple coloured. The white blood cells are responsible for providing defense against various pathogens and micro-organisms that enter our body.
c) Platelets: Platelets appears as faint purple coloured on the slide. These are responsible for the clotting of blood.
Regards