One of the key reasons for Federation was to achieve a united defence force which could better protect Australia. Around the 1880s, the Australian colonies had become increasingly concerned over the close proximity of foreign powers.
Split and merge into it. Answered by The Community. Making the world better, one answer at a time. Dissolved gases trapped in the magma provides the force that causes magma to erupt to the surface. Magma is molten material before it reaches the surface and is lava.
Earthquakes and Volcanoes Key Concept What causes volcanoes to form? Directions: Use the diagram to answer each question on the lines provided. 1. Why does magma move upward? 2. What happens when magma erupts on the surface? 3. What is a volcano? 4. Where do volcanoes form? 5. How is the mid-ocean ridge shown in the diagram formed? 6. How does low pressure cause volcanoes to form? 7.