Here's why:
* Rift Zones: These are areas where the Earth's tectonic plates are pulling apart, creating a gap.
* Magma: As the plates move, the gap allows magma (molten rock) from the Earth's mantle to rise to the surface.
* Volcanic Activity: This magma erupts, forming volcanoes.
* Mountain Chains: Over time, multiple volcanoes can form along the rift zone, creating a chain of mountains.
Examples of Volcanic Arcs:
* The Andes Mountains in South America
* The Cascade Range in North America
* The Aleutian Islands in Alaska
It's important to note that not all mountain chains are formed this way. Some mountains are formed by tectonic collisions, erosion, or other geological processes.
