Antigens are found on cancer cells and the cells of transplanted organs, and an antigen is a protein that prompts an immune response to cancer cells. Given these facts, a protein that prompts an immune response are found where among the following options:
- the skin
 - critical organs
 - epidermis and dermis
 - layers of fat
 - Veins and arteries.
 - at or near the margins
 - Earth orbiting the Sun
 - on cancer cells


 

        on cancer cells 