The immune response of an elderly person becomes weak due to the degeneration of the ...... gland.

What is the process of directly injecting pre-formed antibodies into the body called?

Which of the following statements is incorrect?

Which cells do not produce antibodies but help $B$-cells in the production of antibodies?

Assertion: Interferons are a type of antibodies produced by body cells infected by bacteria.
Reason: Interferons stimulate inflammation at the site of injury.

Match the following columns:

Column-$I$	Column-$II$
$(A)$ Primary lymphoid organs	$(i)$ Thymus
$(B)$ $MALT$	$(ii)$ Spleen
$(C)$ Organ located near the heart	$(iii)$ Bone marrow
$(D)$ Bean-shaped organ	$(iv)$ Appendix
	$(v)$ $50\%$ of lymphoid tissue