Class 12th Biology 2011 Set3 Delhi Board Paper Solution
Question 14
Study the graph given below. Explain how is oxygen concentration affected in the river when sewage is discharged into it.
Study the graph given below. Explain how is oxygen concentration affected in the river when sewage is discharged into it.
Answer
Figure indicates effect of sewage discharge on river water.
As displayed in the figure there is a sharp decline in the amount of O2 concentration at the summit of sewage water and natural water. While as the flow of water moves the amount of O2 increases slowly. Increased amount of O2 lead to the death of zooplankton and phytoplankton species.
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