Answer:
If you're an edge it's multiple choice and it would be c
Question
what is the tallest tower in the world?
Answer
Burj Khalifa in Dubai (2,722 ft)
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.
During the early earth, when photosynthesis has not yet evolved, there were only negligible amounts of free oxygen in the atmosphere. It was said that the Earth's atmosphere had no free oxygen then. This is about 3.5 billion years ago.