The answer to this question is the "coal-burning power or the power plants". Hence, the Airborne mercury has received special attention because it is a widespread and persistent neurotoxin. TA neurotoxin is a substance that damages the brain and the nervous systems. Minute doses can cause nerve damage and other impairments, especially in the young children and the developing fetuses. The majority of the airborne mercury is released by POWER PLANTS or coal-burning plants. Many people are affected and get sick that is why when there is a proposed new power plant project, most people object and opposed.
C. Dependent variable
The independent variable is what you want to change (ex amount of light given to plants)
The dependent variable is what changes because of the independent variable (ex the height of the plants)
So Independent is what you change, Dependent is what you measure