The binding of antibodies to antigens to produce a large insoluble complex is known as:

Match the Column-$I$ with Column-$II$ and select the correct option.

Column-$I$	Column-$II$
$1$. Cellular barrier	$A$. Saliva in the mouth
$2$. Physiological barrier	$B$. Interferons
$3$. Cytokine barrier	$C$. Natural killer (type of lymphocyte)
$4$. Physical barrier	$D$. Mucus coating of the respiratory tract

Which of the following cells act as phagocytes?

An antibody is:

Which of the following are autoimmune disorders?
$A$. Myasthenia gravis
$B$. Rheumatoid arthritis
$C$. Gout
$D$. Muscular dystrophy
$E$. Systemic Lupus Erythematosus $(SLE)$
Choose the most appropriate answer from the options given below:

Acid in the stomach,saliva in the mouth,and tears from the eyes all prevent microbial growth. These belong to which of the following barriers?