(a) Burning of Fossil fuels causes global warming. When fossil fuels are burned, they release nitrogen oxides into the atmosphere, which adds to the formation of smog and acid rain. It contributes directly causing pollution and global warming. Burning of fossil fuel causes both air and water pollution due to the emission of gases like CO2 which is harmful for our environment and can cause green house effect. Also SO2 is released which can result in acid rain which pollutes water bodies.