What is $Agent \ Orange$?

The excessive discharge of fertilizers into water bodies results in

Given below are two statements:
Statement $I:$ In a scrubber,the exhaust from the thermal plant is passed through a spray of water or lime to remove gases like $SO_2$.
Statement $II:$ Particulate matter $(PM\,2.5)$ cannot be removed by a scrubber but can be removed by an electrostatic precipitator.
In the light of the above statements,choose the most appropriate answer from the options given below:

Presence of large amounts of nutrients in waters causes excessive growth of....

It refers to the amount of oxygen that would be consumed if all the organic matter in one liter of water were oxidized by bacteria.

What is the intensity of sound in normal conversation?