The chief regulator of immune mechanism is:

Correct option is C

Ans. (c) Helper T cells
Sol. Helper T cells play a crucial role in regulating the immune response by activating other immune cells like B cells to produce antibodies and macrophages to destroy ingested microbes.
Explanation of each option:
· (a) Plasma cells – Produce antibodies but are regulated by Helper T cells.
· (b) Suppressor T cells – Regulate and suppress the immune response but are not the main regulators.
· (c) Helper T cells – Correct. They coordinate the entire immune response.
· (d) B Lymphocytes – Produce antibodies but depend on Helper T cells for activation.