The primary detrimental effect of the presence of large amounts of biodegradable organic materials in water is __________. (a) it causes death of bottom dwelling organisms because it agglutinates and settles to the bottom, poisoning bottom dwelling organisms (b) it causes oxygen depletion in the water (c) it rises to the surface and absorbs wavelengths needed by aquatic plants (d) it decomposes endothermically causing the temperature of the water to decrease below the limits within which most aquatic organisms can live (e) it causes the water to become murky

The major effect of biodegradable materials pollution of aquatic bodies is the depletion of the oxygen levels in the water. This decline in dissolved oxygen level occurs as a result of the degrading activities of bacteria and other decomposers in the water, using up dissolved oxygen in the process, and as their populations continue to increase, which is mostly exponential, the oxygen levels decrease significantly.

This decrease in oxygen levels cause a selective tolerance of living organisms in the water, as oxygen requiring fishes, algae and plants may not survive due to in-oxygenation, whereas, anaerobic organisms will thrive. also the process of decomposition causes a foul smell in the water bodies with the production of certain gases such as hydrogen, methane, sulfide and ammonia.