Identify the correct statement.

The immune system which works against self is

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.

Which type of immunity is slow and takes time to provide an effective response?

What happens in active acquired immunity?

$A$ person is injected with globulin against hepatitis. This is an example of: