The pathway will be;
The body cells becomes infected with a virus= then new viral proteins appear = class I MHC molecule-antigen complex displayed on cell surface.
Cytotoxic T cell is a T lymphocyte that kills cancer cells, cells that are infected or cells that are damaged in other ways. They are activated on the surface of antigen-presenting cells, which mature during the innate immune responses triggered by an infection.
Answer:
Ecosystems
Explanation:
An ecosystem is where the biotic and abiotic factors live. The other options only contain biotic factors.
External stimulus
The stimulus to which the organism is adapting to is outside of the organism's body.
