Articles > Pollution in Freshwater Ecosystems – Quiz Pollution in Freshwater Ecosystems – Quiz Quiz Choose the best answer. 1. Discharging hot water into the river can increase the temperature and affect the level of oxygen freely available to organisms. True False 2. Heavy rainfall could affect the freshwater as it could be a means for chemicals to enter the stream. True False 3. Litter and foliage could hamper the flow of water as well as block sunlight. True False 4. Discharging toxic wastes into freshwater ecosystem means increased in the concentration of essential chemicals for the growth of organisms. True False 5. One way for a pollution to upset ecological balance is by reducing the overall biomass in the ecosystem. True False Send Your Results (Optional) Your Name To Email Time's up