Which wave has a disturbance that is only parallel to the wave motion?

this is a good question! i'll do some research and come back when i have the answer!

i think the answer is a, hope this : )

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