premise: the continental crust mainly is made of granite sent2: exposure to extreme heat and pressure changes igneous rock into metamorphic rock sent3: continental crust is a kind of crust sent4: two tectonic plates pushing toward each other cause intense heat and pressure in earth's crust sent5: rock is a kind of material sent6: the crust is made of different kinds of crust sent7: basalt is a kind of igneous rock sent8: the crust is a layer of the earth sent9: the oceanic crust mainly is made of basalt.
hypothesis: neutrons add mass to the nucleus