While electricity created through hydropower is cheap, clean and renewable, blocking entire rivers for the sake of electricity has its environmental costs. National Parks quiz From A to Z, Arches to Zion, America's national parks range from vast to small, from focal points of history to sites of extraordinary natural beauty. Basic genetics quiz One of the greatest areas of scientific discovery in recent years may not be in outerspace or the deep sea, but lies instead within the uncharted terrain of the human body. Genetically modified food accounts for a significant portion of all food produced in the United States and may well constitute a portion of your daily diet. Like the wolf and grizzly bear, salmon are a symbol of nature in its original, wild state.
Outdoor activities add tremendously to health, fitness and general well-being.
Exposure to the sun can damage the body in many ways. The nature and condition of Earth's atmosphere is the source of intense research and debate. Every discipline of study has a unique vocabulary. The world of ecology is no different from the rest. With words that convey how organisms relate to each other and the environment, the language of ecology is colorful and dynamic.