GEOLOGY

Detailed explanation-1: -This increase happens because the coal or oil burning process combines carbon with oxygen in the air to make CO2. To a lesser extent, clearing of land for agriculture, industry, and other human activities has increased concentrations of greenhouse gases.

Detailed explanation-2: -Carbon dioxide is added to the atmosphere naturally when organisms respire or decompose (decay), carbonate rocks are weathered, forest fires occur, and volcanoes erupt. Carbon dioxide is also added to the atmosphere through human activities, such as the burning of fossil fuels and forests and the production of cement.

Detailed explanation-3: -Increased use of fossil fuels and deforestation both has led to an increase in carbon dioxide content in the atmosphere which leads to greenhouse effect and global warming.

Detailed explanation-4: -In an agricultural system, carbon is cycled through the atmosphere, through plants and animals, and through the soil. The production of food affects the amount of carbon in the soil as harvesting plant and animal products removes carbon from the agricultural system.