The immune system:

The term 'active immunity' means

Which barrier of innate immunity is represented by saliva in the mouth and tears in the eyes?

$A$ newborn infant shows passive acquired immunity against many diseases because:

Arrange the steps of the $phagocytosis$ process in the correct sequence.
$(a)$ Ingestion of microbes by phagocytes
$(b)$ Dilation of blood vessels by histamine
$(c)$ Formation of $phagosome$ and $phagolysosome$
$(d)$ Migration of phagocytes into $E.C.F.$
$(e)$ Attraction of phagocytes by $chemotoxins$ secreted by microbes
$(f)$ Intracellular destruction of bacteria

What are $IgA$ and $IgE$?