Which one of the following is the correct percentage of the two green house gases that contribute to the total global warming?

N2O-6%, CO2 -86%
Methane-20%, N2O-18%
CFCs -14%, Methane-20%
CO2-40%,CFCs-30%

The correct answer is A. N2O-6%, CO2 -86%.

Nitrous oxide (N2O) is a greenhouse gas that is produced by natural processes such as soil cultivation and the decomposition of organic matter. It is also produced by human activities such as the burning of fossil fuels and the use of nitrogen fertilizers. N2O is a powerful greenhouse gas, with a global warming potential of 298 times that of carbon dioxide.

Carbon dioxide (CO2) is a greenhouse gas that is produced by the burning of fossil fuels, such as coal, oil, and natural gas. It is also produced by natural processes such as respiration and the decomposition of organic matter. CO2 is the most important greenhouse gas, accounting for about 80% of the total greenhouse gas emissions from human activities.

The other options are incorrect. Option B states that methane (CH4) contributes 20% of the total greenhouse gas emissions. However, CH4 actually contributes about 16% of the total greenhouse gas emissions. Option C states that chlorofluorocarbons (CFCs) contribute 14% of the total greenhouse gas emissions. However, CFCs have been banned since the 1980s and now contribute very little to greenhouse gas emissions. Option D states that CO2 contributes 40% of the total greenhouse gas emissions and CFCs contribute 30% of the total greenhouse gas emissions. However, CO2 actually contributes about 80% of the total greenhouse gas emissions and CFCs contribute very little to greenhouse gas emissions.