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.TrueFalse 2. Heavy rainfall could affect the freshwater as it could be a means for chemicals to enter the stream.TrueFalse 3. Litter and foliage could hamper the flow of water as well as block sunlight.TrueFalse 4. Discharging toxic wastes into freshwater ecosystem means increased in the concentration of essential chemicals for the growth of organisms.TrueFalse 5. One way for a pollution to upset ecological balance is by reducing the overall biomass in the ecosystem.TrueFalse Send Your Results (Optional) Your Name To Email Time is Up!