Which statement best explains why magma rises to the surface?

• A. It is less dense than surrounding solid rock
• B. It is heavier than surrounding rocks
• C. It is cooled by Earth's surface
• D. It is attracted by gravity to the center

Answer: (A)

Magma rises because of buoyancy: it is less dense than the surrounding solid rock, so the upward buoyant force on the melt exceeds its weight. This density difference makes magma float and push upward through the mantle and crust, gathering in magma chambers and moving toward the surface along cracks and conduits. The other ideas don’t fit because being heavier would pull magma downward, cooling by the surface would slow or stop ascent rather than drive it upward, and gravity toward the center is a general pull that doesn’t explain why the less-dense magma rises relative to surrounding rock.