Where is mucosa-associated lymphoid tissue (MALT) located?

The correct answer is Option (4) → Lining of major tracts (respiratory, digestive, and urogenital tracts)

Lymphoid organs are where lymphocytes are formed, mature and meet antigens. The primary ones are the bone marrow and the thymus; the secondary ones include the spleen, lymph nodes, tonsils and Peyer’s patches. Apart from these organs, lymphoid tissue also lies in the lining of the major tracts of the body. These tracts open to the outside and receive many microbes, so this tissue guards the entry points. It is called MALT (mucosa-associated lymphoid tissue).

NCERT Extract:
Immune System in the Body – “… There is lymphoid tissue also located within the lining of the major tracts (respiratory, digestive and urogenital tracts) called mucosa-associated lymphoid tissue (MALT). It constitutes about 50 per cent of the lymphoid tissue in human body.”