Some people who have suffered from a disease may not be affected again during their life time; such immunity is called

"Graveyard of $RBCs$'' 

$T$-cells are lymphocytes which produce the cellular immunity. These are developed from

Given below are two statements :

Statement $I$ : Bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced.

Statement $II$ : Both bone marrow and thymus provide micro environments for the development and maturation of T-lymphocytes.

In the light of above statements, choose the most appropriate answer from the options given below :

Antivenom injection contains preformed antibodies while polio drops that are administered into the body contain

After vaccination the body builds up