Question

The graph given below represents the effect of sewage discharge on some important characteristics of river.

Select the correct option with respect to the peaks A and B.

• A. Peak $A$ - Sharp increase in $BOD$, disappearance of clean water organisms
  Peak $B$ - Increase in dissolved oxygen, reappearance of clean wter organisms
• B. Peak $A$ - Increase in dissolved oxygen, reappearance of clean water organisms
  Peak $B$ - Sharp decline in dissolved oxygen, disappearance of clean water organisms
• C. Peak $A$ - Sharpin creasien $BOD$, appearance of clean water organisms
  Peak $B$ - Increase in dissolved oxygen, disappearance of clean water organisms
• D. Peak $A$ - Increased number of anaerobic bacteria, disappearance of clean water organisms
  Peak B - Sharp decline in dissolved $O_2$, reappearance of clean water organisms

Answer 1

Answer: (A)

Correct answer is (a) Peak $A$ - Sharp increase in $BOD$, disappearance of clean water organisms
Peak $B$ - Increase in dissolved oxygen, reappearance of clean wter organisms