In the treatment of wastewater,scientists at the Arcata Marsh (a project associated with Humboldt State University) developed a series of six connected marshes over how much area to remove heavy metals and other pollutants?

What is Agent Orange?

Eutrophication results in the reduction of

'Heat islands' are produced due to

Spraying of pesticide is an example of

Given below are two statements:
Statement $I$: Electrostatic precipitator is most widely used in thermal power plants.
Statement $II$: Electrostatic precipitator in thermal power plants removes ionising radiations.
In the light of the above statements,choose the most appropriate answer from the options given below: