You are presented with the question "a protein that prompts an immune response are found where?" and the following answer choices: 
- 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

Now knowing that 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, choose the best answer.


 

        on cancer cells 