7th Class Science Sample Paper Science Sample Paper - 3

  • question_answer
    What are the harmful effects of releasing untreated sewage in water bodies?

    Answer:

    Untreated excreta contaminates water. It encourages algae bloom in water bodies. The water of such water bodies becomes unfit for drinking and other household purposes. Such water also causes large number of water borne diseases such as typhoid, cholera, hepatitis and polio, etc.   


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