Which of the following statements is incorrect?

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:

The grafting principle depends upon the

When an insect bites,the affected area swells. Which chemicals are likely introduced into the body?

Which cells are responsible for acquired immunity?

Antigen binds to antibody. The binding is the result of