What percentage of lymphoid tissue in the human body is constituted by Mucosa-Associated Lymphoid Tissue $(MALT)$ (in $\%$)?

What are the characteristics of acquired immunity?

Read the following statements and choose the correct set of statements $:$
$(a)$ Cell-mediated immune response is responsible for the graft rejection.
$(b)$ Grafts from just any source $-$ an animal,another primate,or any human beings can be made since the grafts would be accepted sooner or later.
$(c)$ The organs cannot be taken from just anybody for transplant.
$(d)$ Tissue matching,blood group matching are essential before undertaking any graft/transplant.
Choose the correct answer from the options given below $:$

$T$-Lymphocytes originate from

In the case of a snakebite,what is injected into the patient?

Which of the following provides the microenvironment for the maturation of $T$-lymphocytes?