What type of barrier is the mucus coating?

Identify the set of secondary lymphoid organs from the following.

Match the following columns:

Column-$I$	Column-$II$
$P$. Physical barriers	$I$. Acid in stomach,saliva in mouth,tears from eyes
$Q$. Physiological barriers	$II$. Skin,mucus coating of epithelium lining the respiratory,gastrointestinal and urogenital tracts
$R$. Cellular barriers	$III$. Interferons
$S$. Cytokine barriers	$IV$. Polymorphonuclear leukocytes ($PMNL$-neutrophils),monocytes,$NK$ cells,macrophages

Differentiate between the following and provide examples for each:
$(a)$ Innate and acquired immunity
$(b)$ Active and passive immunity

Identify the cell that induces the process of $cytolysis$.

Which type of antibody is produced in the body against the body's own cells in rheumatoid arthritis?