1. Sulfur dioxide and nitrogen oxides are the primary causes of acid rain. Acid rain occurs when these gases react in the atmosphere with water, oxygen, and other chemicals to form various acidic compounds. Sunlight increases the rate of most of these reactions. The result is a mild solution of sulfuric acid and nitric acid. Acid rain is a global problem because it has been shown to have adverse impacts on forests, freshwaters and soils, killing insect and other life forms as well as causing damage to buildings and having impacts on human health. Badly affected places around the globe include most of Europe, many parts of the U.S. in New York and south west Canada.
5. A tornado is a localized, violently destructive windstorm occurring over land, esp. in the Middle West, and characterized by a long, funnel-shaped cloud extending toward the ground and made visible by condensation and debris. The United States has the most tornadoes of any country. Europe, Australia, China, Japan, South Africa, and Argentina are other regions where tornadoes are most likely to occur.
6. Ozone is a gas in the atmosphere that protects everything living on the Earth from harmful ultraviolet rays from the Sun. Without the layer of ozone in the atmosphere, it would be very difficult for anything to survive on the surface. Plants cannot live and grow in heavy ultraviolet radiation, nor can the plankton that serve as food for most of the ocean life. The ozone layer is important because it acts as a shield to absorb the UV rays, and keep them from doing damage at the Earth's surface. Chlorine and bromine released from man-made compounds such as CFCs are the main cause of the depletion.
8. The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere such as water vapor, carbon dioxide, nitrous oxide, and methane trap energy from the sun. Without these gases, heat would...