Soil which is the surface layer of earth results from the degradation of rock and is filled with life. A billion organisms exist in one square meter of fertile soil. Small mammals, worms and insects tunnel in the soil and provide air circulation. Microorganisms such as algae, bacteria and fungi decompose organic matter making minerals available to the roots of plants. The soil is a true ecosystem and is easily destroyed by pollution.

Originally released by QA International, 2005. Streaming video file encoded with permission for digital streaming by Infobase on May 06, 2015.

Soil (1:00);.