Solar power is simply the use of sunlight to create electricity. The Earth and our solar systemget most of their energy from the Sun. The Sun, as the source of solar and most other forms ofrenewable energy, will continue to shine for some billions of years. The Sun shines on plants,giving them the energy they need to grow and thrive. Animals then eat plants, which gives themenergy, too. Many of the Earth resources are used for energy. Wind, sun, water and fire are all sources of energy. In the United States, the most used sources of energy are fossil fuels such as coal andoil. Although oil gives us the gasoline that runs our cars, the huge consumption of fossil fuelshas caused visible damage to the environment in various forms like air pollution. Many scientists are working to develop new ways of providing energy without damaging theEarth. Through advances in the research of alternative energy sources, the world is slowlychanging from using fossil fuels to using wind power, water power, and solar energy. Windmills are used to capture wind power. Dams help to get the energy from water. Solarpanels collect energy from the Sun’s rays and keep it stored for future use. These are somekinds of renewable energy that we call “clean” because they produce few if any types ofpollution. (*-****) What does the passage mainly discuss?