Which of the following are included in primary lymphoid organs?

Which type of innate barrier does the $Stratum$ $corneum$ represent?

Select the option that correctly matches the example with its specific type of immunity barrier.

Match the following columns:

Column-$I$	Column-$II$
$(A)$ Physical barriers	$(1)$ Interferon
$(B)$ Physiological barriers	$(2)$ Leukocytes
$(C)$ Cellular barriers	$(3)$ Tears
$(D)$ Cytokine barriers	$(4)$ Skin

The antibodies are produced by the

Assertion $(A)$: The human body is exposed to a large number of infectious agents daily,yet only a few result in disease. Reason $(R)$: The human body possesses an immune system. Which option is correct for Assertion $(A)$ and Reason $(R)$?