Which of the following provides a micro-environment for the maturation of $T$-lymphocytes?

The letter $T$ in $T$-lymphocyte refers to:

Which of the following is a primary lymphoid organ?

Given below are two statements:
Statement $I:$ Autoimmune disorder is a condition where the body's defense mechanism recognizes its own cells as foreign bodies.
Statement $II:$ Rheumatoid arthritis is a condition where the body does not attack self-cells.
In the light of the above statements,choose the most appropriate answer from the options given below:

In which of the following organs do immature lymphocytes differentiate into antigen-sensitive lymphocytes?

Interferons were first discovered from cells infected with which of the following?