Why is granite much more common than rhyolite?
b) felsic magma is very viscous and is more likely to solidify underground than to erupt at the surface.
 

Which would you expect to be most explosive?
b) a volcano at a convergent plate boundary

Partial melting produces magma that has less silica than the rock being melted.
b) false

Obsidian is one of the few rocks not composed of minerals.
a) true

Which of the following applies to rocks with porphyritic textures:
b) slow cooling following by fast cooling
 

Explosive volcanoes eject ash and bombs, which are called:
a) pyroclastic materials

Composite volcanoes are found at:
c) convergent plate boundaries
 

When lava is quickly chilled underwater, it forms what is known as:
a) pillow basalt (or lava)