Chapter 57, Problem 3A

If a pesticide is harmless at low concentrations (such as DDT) and used properly. how can it become a threat to nontargct organisms?

a. Because after exposure to DDT. some species develop allergic reactions even at low levels of exposure

b. Because DDT molecules can combine so that their concentration increases through time

c Because the concentration of chemicals such as DDT is increasingly concentrated at higher trophic levels

d. Because global warming and exposure to UV-B radiation renders molecules such as DDT increasingly potent