An ant moved 2m in 50s, is this velocity or speed ?

This is the speed. 2m per 50 seconds.

It would be speed

layers of the earth affect the waves and these effects are seen on instruiments such as seimometers

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