premise: great can mean high in value sent2: underground means buried deep below other rocks sent3: exposure to pressure is a kind of condition sent4: exposure to heat is a kind of condition sent5: a site is a kind of area sent6: metamorphic rocks are formed by rocks being exposed to extreme heat and pressure sent7: extreme means very high in value sent8: deep means great in depth sent9: if something is formed by certain conditions then that something will likely be formed in an area with those conditions.
hypothesis: the equator will have higher temperature than the poles on earth