Question

what causes the force that pushes magma from the magma chamber through the pipe and vent of a volcano?
gravity
water flow
expanding gases
convergent boundaries

Explanation:

To determine the force pushing magma, we analyze each option:

• Gravity: Primarily acts downward, not the main force for upward magma movement.
• Water flow: Not a primary force in magma movement from the chamber.
• Expanding gases: As magma rises, pressure decreases, causing dissolved gases (like water vapor, CO₂) to expand, creating pressure that pushes magma through the pipe/vent.
• Convergent boundaries: Are plate boundaries, not the direct force pushing magma from the chamber.

So expanding gases are the cause.

Answer:

C. expanding gases