This document discusses soil composition and properties, noting that soil is composed of minerals, air, water, and organic matter. It explains that soil formation occurs over long periods of time as parent material weathers and decomposes. The document provides a link to further information about soil composition and properties on an education website.

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:
http://portal.edu.chula.ac.th/lesa_cd/assets/document/LESA212
/8/soil/passing_through/passing_through.html
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