Which of the following is not a way to avoid exposure to carcinogens?
a. avoid smoking
b. eat healthy foods
c. stay physically active
d. perform self-examinations

Performing self-examinations is not a way to avoid exposure to carcinogens. It is simply a method or something that you can do to check if you have cancer due to exposure to carcinogens. You can avoid late treatment or late diagnosis, but that does not help you avoid exposure. 

The answer to your question is D. 

Blood transfusions were rarely done and often fatal; they were outlawed until the nineteenth century.

Lifting and pull ups