Ecosystems include producers, consumers and decomposers. Decomposition is one of nature's recycling methods. The earth's surface is mostly water in the form of oceans, seas, lakes, rivers, ponds, streams and glaciers. Only a small amount of fresh water is available for use. Human health and ecosystems are affected by litter and pollution.
Resources are either renewable or non-renewable.
Landfills are used for the disposal of solid waste. Reduce, Reuse, and Recycle are ways to reduce waste. People of different races, cultures and genders have contributed to our environmental awareness. The lever, inclined plane, pulley, wedge, gear and wheel and axle, are simple machines. Force can be measured.