Antibodies are produced by

Vaccination protects a person from disease because it...

Identify the correct statement.

Long-term immunity against pathogens is provided by which of the following?

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.

In vaccination,inactive or dead antigens are introduced into the body. What type of immunity is this?