Which of the component does not belong to the second line of defense? 

Statement (S): Natural killer cells form the body's most important cells of defence, and they destroy the infected cells or altered self cells in an antibody-independent manner.

Reason (R): The reaction time of NK cells is fast as they are always in an active form to identify and destroy even small cancer cells well before they form a tumor.

Which of the following is true?

Match the following:

The correct match is

Read the following statements
I) ${\mathrm{T}}_{\mathrm{C}}$ lymphocytes are involved only in cell mediated immunity.
II) Thymus gland of mammals is a secondary lymphoid organ.
III) The part of antibody that recognises and binds to an antigen is called epitope.
IV) Interleukins are primarily involved in differentiation of the cells of immune system.

Among the above, the incorrect statements are

Match the following about immune system

The correct answer is

Study the following:
Statement $\mathrm{I}$: ${\mathrm{T}}_{\mathrm{H}}$ cells are involved in humoral and cell mediated immunity.
Statement $\mathrm{II}$ : Natural killer cells are a type of lymphocytes.

The correct option among the following is