You are presented with the question "What can be found on cancer cells?" and the following answer choices: 
- acetic acid
 - Allergies
 - bacteria
 - parasites
 - fever
 - PDAs
 - proteins
 - bioaerosols

Now knowing that antigens are found on cancer cells and the cells of transplanted organs and aLL proteins are antigens, choose the best answer.


 

       proteins  