Why do masses of partially melted rock or magma rise or intrude the surrounding rocks?

Explained

Explanation:

The melted magma or partially melted rock rise or intrude the surrounding rocks because of the buoyancy. The partially melted rocks or magma due their high temperature become less dense than the surrounding rocks and rise up. And then these heated rock or magma react with surrounding rocks which in turn increases the pressure in the magma chamber. This intermixing of magma with surrounding rocks forms another type of rocks called igneous rocks.