Ultramafic rocks contain and are commonly found in

Ultramafic rocks contain "olivine," and are commonly found in "mantle."
mantle is a inner layer of a planet and makes up about 84% of the planet. Ultramafic rocks are found in layers, so naturally you will find this in the mantle layer of the planet.

This would be an open primary. a closed primary people can vote only prior to election day if the party if they are registered. independent voters can not participate. there is not a wide-open primary, but there is a semi-open primary.

Answer they are produced by collision of tectonic plates;