ESAY+3.1

=Volcanoes and plate tectonics=

vocabulary

 * What is a volcano**:- Openings in the surface of the earth which magma and gases can escape Pressure in the mantle forces magma to the surface. Occurs where magma finds a way through a crack or weakness in the earth's crust.This is usually at the earth's crust

OUTLINE:-

 * There are about 600 volcanoes on land
 * many more lie beneath the sea
 * one major volcano belt is ring of fire
 * most volcanoes occur along diverging plate boundaries ,such as the mid -ocean ridge or in subduction zones around the edges of oceans