Orders of steps in T cell response:
Step 1. D. Pathogen enters the body
Step 2. C. Helper T cells recognize antigens from a foreign invader
Step 3. B. Helper T cell start production of cytotoxic T cell
Step 4. A. Cytotoxic T cells kill infected body cell
T cells are an essential part of the immune system and it focuses on specific foreign material that enters the cell. The response includes three major stages and these are activation, differentiation, and memory formation.