Choose from:
(a). heat energy.
(b). direct energy.
(c). Energy.
(d). massive damage.
(e). rays or beams.
(f). antibodies.
(g). Energy..
(h). Chemical energy.

Fact 1: Antigens are found on cancer cells and the cells of transplanted organs. Fact 2: Antibody production is triggered by antigens. Given the two facts above, what do cancer cells produce?
Answer:
(f).