$WBC$ is an example of

$A$ patient rejects a transplanted kidney because of ..........

Grafting between two members of the same species is known as:

In an antibody,disulphide bonds are present . . . . . .
$i$. between two heavy chains
$ii$. between two light chains
$iii$. between the constant region of a light chain and the constant region of a heavy chain
$iv$. between antigen binding sites of both the heavy and light chains
$v$. between the variable region of a light chain and that of a heavy chain
Select the correct answer from the options given below.

Acquired immunity is mediated by which of the following?

In vaccination,which of the following is introduced into the body?