Explanation:
Volcanoes erupt because of when molten rock(magma) rises to the surface causing bubbles of gas to form.
The inner core is solid because it is made of very dense, or heavy, materials - like iron and nickel. Even though it is very hot, these materials don't "melt" very easily, so they stay solid. Also, pressure due to the weight of the mantle and crust, atoms are forced together as solid.
The Pacific Ocean Basin is rimmed by the most subduction zones.