What is the cause of Multiple Sclerosis?

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.

Which of the following cells act as phagocytes?

Who is known as the father of passive immunity?

In the case of a snakebite, the patient is injected with preformed antibodies against the snake venom. This type of immunity is called.........

What type of cells are the $B$-cells and $T$-cells of the immune system?