Lymph nodes are responsible for fighting against which of the following?

Which cell of the immune system causes pore formation at the surface of the plasma membrane of target cells?

Which of the following are primary lymphoid organs?

Given below are two statements.
Statement $I$: Passive immunity is acquired when readymade antibodies are received by body cells.
Statement $II$: Resistance induced by $BCG$ vaccine is an example of passive immunity.
In the light of the above two statements,choose the correct answer from the options given below.

Antibodies produced by $B$-lymphocytes are responsible for:

Which of the following statements is incorrect regarding antibodies?