Read the following passage and answer the question :
The primary lymphoid organs are bone marrow and thymus, where immature lymphocytes differentiate into antigen sensitive lymphocytes. They migrate to secondary lymphoid organ like spleen, lymph nodes, tonsils, Peyer’s patches of small intestine and appendix. All blood cells including lymphocytes are produced in bone marrow which is main lymphoid organ. Spleen is large reservoir of erythrocytes. It is large bean shaped organ mainly containing lymphocyte and phagocyte. It acts as filter of blood by trapping blood borne micro organism. Lymph nodes are small solid structures located at different points along lymphatic system. Antigens trapped in lymph node are responsible for activation of lymphocytes present there and cause the immune response. There is lymphoid tissue located within. Lining of major tracts like respiratory, digestive and urogenital tracts called mucous associated lymphoid tissue (MALT).
Which of the following is incorrect statement.
(A) All blood cells including lymphocytes are produced in bone marrow
(B) Lymph nodes are small solid structures located at different points along lymphatic system
(C) Peyer’s patches of small intestine is primary lymphoid organ.
(D) Antigen trapped in lymph node are responsible for activation of lymphocytes present in lymph node and causes immune response .
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (C) only
(A) All blood cells including lymphocytes are produced in bone marrow — A correct statement. The bone marrow is the main lymphoid organ where all blood cells are made.
(B) Lymph nodes are small solid structures located at different points along lymphatic system — A correct statement. They catch microbes and antigens in the lymph.
(C) Peyer’s patches of small intestine is primary lymphoid organ. — An incorrect statement. Peyer’s patches are secondary lymphoid organs. The primary lymphoid organs are only the bone marrow and thymus, where lymphocytes mature.
(D) Antigen trapped in lymph node are responsible for activation of lymphocytes present in lymph node and causes immune response. — A correct statement. The trapped antigens activate the lymphocytes there.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.