A symbiotic relationship that involve species having to fight for something they both need or want

igneous rocks also form where plates converge. the subducting plate melts as it sinks into the crust of the earth, and the melt rises into the overriding plate forming volcanoes. metamorphic rocks are formed mainly in the lithosphere, wherever there is high pressure and high temperature. -woods

snell's law

refractve index = sin incidence / sin refraction