4. D since its basically the bottom one
Answer:
Cytotoxic T cell
Helper T cell
Explanation:
Adaptive immune system is a part of the immune system initiated only when there is an attack by a pathogen or foreign substance. The adaptive immune system is beckoned on when the infection is insurmountable for the body's first line of immunity, which is the innate immune system.
The adaptive immune response is triggered by the white blood cells called LYMPHOCYTES. Lymphocytes consists of T cells and B cells. T cells are either cytotoxic or helper T cells. The cytotoxic T cells kills the cells infected with the virus while the Helper T cells activate every other cell involved in the immune process.
