Sedimentary rocks develop from eroded grains of other rocks and organic matter. Metamorphic rocks are the third main classification. These started out as other types of rock but were changed by ...

Sedimentary rocks close sedimentary rockSedimentary ... causing them to change into another type of rock. They are usually resistant to weathering and erosion and are therefore very hard-wearing.

A compound is a substance that contains two or more elements close elementA pure substance that is made from only one type of atom ... s causeway is an igneous rock. Sedimentary rocks are formed ...