what causes the force that pushes magma from the magma chamber through the pipe and vent of a volcano?\no…

Brief Explanations:

Magma in a volcano contains dissolved gases. As the magma rises towards the surface, the pressure decreases, causing the gases to expand. This expansion generates the force that pushes the magma through the pipe and vent. Gravity would pull magma downwards, water - flow is not the main factor here, and convergent boundaries are related to plate tectonics but not the direct force for magma movement in a volcano.

Answer:

C. expanding gases