SSC Ecology And Environment Sample Paper NCERT Sample Paper-2

  • question_answer
    If the river water is polluted with domestic sewage and garbage it leads to the depletion of

    A)  \[C{{O}_{2}}\]

    B)  \[CO\]

    C)  \[{{O}_{2}}\]              

    D)  All the above

    Correct Answer: C

    Solution :

    [c] River water polluted with domestic sewage and garbage leads to increase in temperature of the river, which is termed as Thermal Pollution. Thermal pollution is defined as sudden increase or decrease in temperature of a natural body of water which may be ocean, lake, river or pond by human influence. This normally occurs when a plant or facility takes in water from a natural resource and puts it back with an altered temperature. Usually, these facilities use it as a cooling method for their machinery or to help better produce their products. The warm temperature reduces the levels of DO (Dissolved Oxygen) in water. The warm water holds relatively less oxygen than cold water. The decrease in DO can create suffocation for plants and animals such as fish, amphibians and copepods, which may give rise to anaerobic conditions. Warmer water allows algae to flourish on surface of water and over the long term growing algae can decrease oxygen levels in the water.

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