Grafting of tissue or organ between individuals of different species is called

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:

Perforin is secreted by which of the following cells to prevent the effect of microbes?

In active acquired immunity,.........

The interferon of other animals: