The correct answer is - the change of the total volume of water in the Earth's system.
The total volume of the water in the Earth's system is pretty much the same, and for it to change, and change the levels of the water in the oceans and seas, the Earth will have to go over a totally new conditions where either a new influx of water will reach our planet, or the heat will increase and the water will evaporate, for now that is not a possibility.
Answer: Ozone is considered as chief polluting gas.
Explanation:
The ozone is a ground level pollutant. It is a colorless gas. It causes irritation in the eyes and respiratory tract. It is one of the components of smog as it causes pollution in the atmosphere. It is produced by the two primary pollutants that are nitrogen oxides and volatile organic compounds when they react with the sunlight. The ozone makes the air irrespirable. It is the main cause of throat irritation, labored breath, pain in chest and also responsible for respiratory diseases. It reduces the body's ability against infection. The ozone depleting substances like aerosol, chlorofluorocarbon are widening the ozone depleting zone as halides present in these substances react with the ozone causing depletion. This allows the entry of harmful ultraviolet radiation penetrating the atmospheric layers.
Mount Rushmore is located in the Black Hills :)
