Click to review the online content. Then answer the question(s) below, using complete sentences. Scroll down to view additional questions. Online Content: Site 1 Online Content: Site 2 Online Content: Site 3 What are the factors that determine the level of harm an introduced chemical has on the environment? (Site 1) Why is nonpoint source pollution difficult to control? (Site 2) What are the consequences of increased nitrogen and phosphorus into water systems? (Site 3)