Which of the following are Autoimmune disorders?

$A$. Myasthenia gravis  $B$. Rheumatoid arthritis

$C$. Gout  $D$. Muscular dystrophy

$E$. Systemic Lupus Erythematosus ($SLE$)

Choose the most appropriate answer from the options given below:

For an organ transplant, it is an advantage to have an identical twin. Why ?

Which of the following immunoglobulins does constitute the largest percentage in human milk ?

What is the basic principle of vaccination ? How do vaccines prevent microbial infections ? Name the organism from which hepatitis $B$ Vaccine is produced.

Each antibody has $…A…$ polypeptide chains, $…B…$ small chains called $….C…$ chains and $…D…$ longer chains called $.E…$ chains

The antibody, therefore, is represented as $…F…$

Here $A$ to $F$ refers to