The correct answer is A. CFC emission.
CFCs are chlorofluorocarbons, which are chemicals that were once used in refrigerators and air conditioners. They were banned in the 1980s because they were found to be damaging to the ozone layer. The ozone layer is a layer of gas in the atmosphere that protects the Earth from harmful ultraviolet radiation from the sun. CFCs are not a cause
of present global warming and climate change because they have been banned for many years.B. Carbon dioxide emission is a cause of
present global warming and climate change. Carbon dioxide is a greenhouse gas that traps heat in the atmosphere. When humans burn fossil fuels, such as coal, oil, and natural gas, they release carbon dioxide into the atmosphere. This increase in carbon dioxide levels is causing the Earth’s temperature to rise.C. Deforestation is also a cause of present global warming and climate change. When trees are cut down, they no longer absorb carbon dioxide from the atmosphere. This release of carbon dioxide into the atmosphere contributes to global warming.
D. Methane emission is another cause of present global warming and climate change. Methane is a greenhouse gas that is even more potent than carbon dioxide. When methane is released into the atmosphere, it traps heat and contributes to global warming.