Question

The water pollution in river is measured by the dissolved amount of
1.Chlorine 2.Oxygen 3.Nitrogen 4.Ozone

Answer 1

Chemical Oxygen Demand(COD) and Biological Oxygen Demand(BOD). ... Water pollution can also be measured by the aquatic habitat present in the water sample.

Answer 2

The water pollution in river is measured by the dissolved amount of oxygen. this is known as DO test . hence, option (2) is correct option.