$MALT$ constitutes about ................. of the lymphoid tissue in the human body. (in $\%$)

Which of the following are secondary lymphoid organs?
$(a)$ Bone marrow
$(b)$ Tonsils
$(c)$ Spleen
$(d)$ Thymus
Choose the correct answer from the options given below:

Antibodies are ........

Which cells are responsible for the immune response of the body?

Breastfeeding can be categorized under which type of immunity?

Which of the following is a primary lymphoid organ?