Which of the following are the most abundant types of antibodies?

Assertion $A$: Cell-mediated immunity is responsible for the rejection of organ transplants. Reason $R$: The body's immune system has the ability to differentiate between self and non-self. Which option is correct for Assertion $A$ and Reason $R$?

If you suspect a major deficiency of antibodies in a person,to which of the following would you look for confirmatory evidence?

Vaccination provides protection to an individual against a disease because it.........

Identify the correct statement$(s)$ regarding the human immune system.

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