Question

The main function of white blood cells is
(a)To help red blood cells in the transportation of oxygen and carbon dioxide.
(b)To clot the blood at the time of injuries
(c)To accelerate the production of red blood cells in the bone marrow
(d)To defend the body against infections

Answer 1

Hint: WBC is always at war; they can be considered as the soldiers of the body. They show properties like phagocytosis and diapedesis. They are of many types and related to the maintenance of health in an organism.

Complete answer:
WBC accounts for about 1% of the body's blood but they play an integral role in body functioning. They are also called leukocytes. And their function is to defend the body against infections. They can be considered as the immunity cells.
WBCs are very small in size and can show amoeboid movement by which they can change their shapes according to the environment needs hence they can squeeze through the walls of the blood vessels.
WBCs are further grouped into their major classes namely – Lymphocyte, Granulocyte, and monocyte.
The lymphocyte is responsible for directly kills foreign invaders.
Monocytes migrate into the tissues and clean up the dead cells.
Granulocytes are the first line of defense and defend the body against foreign invaders. A characteristic feature of these cells is the presence of cytoplasmic granules.

So, the correct answer is,’ To defend the body against infections.’

Note: New-borns have a high white blood cell count that gradually falls to the adult level during the childhood stage. Stem cells in the bone marrow are responsible for producing white blood cells. On encountering the inflammation, the body releases the white blood cells to help fight the infection.