8. WHY DO SOME VOLCANOES EXPLODE, WHILE OTHERS EMIT ONLY GASEOUS CLOUDS?

Some volcanoes explode because the magma that is beneath them is physically forced out of the volcano and into the air. Also, some volcanoes have a core or cap that was formed long ago that holds magma back until it can reach a pressure high enough for it to explode outward. Other volcanoes release only gas because there are pockets of gas and ash trapped above the magma chamber, but below the surface of the volcano. This is released instead of magma and the pressure below the volcano is released as well.

9. HOW DO the LAVAS ERUPTED by VOLCANOES in OCEAN BASINS DIFFER FROM THOSE in ISLANDS AROUND the BORDER of the PACIFIC?

The ocean basin volcanoes mostly eject basalt and other iron-based magma due to the fact that they are near subduction zones and fissures in the Earth's...

The islands around the border of the pacific have a much more granitic composition, caused by the wearing down of the earth's crust as well as uplifts and crustal folding. These types of volcanoes also form near subduction zones but they include other types of rock that have higher concentrations of aluminum and granite-based compounds,
10. HOW CAN SO MANY DIFFERENT TYPES of IGNEOUS ROCKS ORIGINATE FROM a SINGLE BASALTIC MAGMA?

Many different types of rock originate from basalt magma through metamorphosis. These metamorphic rocks start as igneous magma, but because of their unique composition, temperature and pressure exposures, they begin to change and form other types of rock over time. Also, different minerals and substances are eventually mixed in and create all different types of metamorphic compounds like granite.