Antibodies in our body are complex of ........

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:

Which cells are responsible for producing antibodies?

The toxic substances produced by foreign bodies that trigger an immune response are known as:

What is the full form of $MALT$?

What are the two corollaries related to the immune system?