Which antibody is known as the secretory antibody?

Which of the following cannot be included in the cellular barrier of innate immunity?

Which of the following statements are correct regarding the structure and types of antibodies in humans?
$i$. Antibodies are also called Immunoglobulins that are produced as an immune response to antigenic stimulation.
$ii$. They are produced by all types of $T$-lymphocytes and $B$-lymphocytes.
$iii$. An antibody is a $Y$-shaped molecule formed of four polypeptide chains. Antibodies present in plasma determine many blood group systems like $ABO$,$Rh$,$P$,$MNS$ etc.
$iv$. An antibody molecule consists of two antigen-binding sites called paratopes.

How many types of barriers are included in innate immunity?

Which of the following immune responses is responsible for the rejection of a kidney graft?

Animals develop immunity in their bodies to combat diseases during their lifetime after birth. This is called.........