The answer is B. folding, uplift, and erosion. certain mountains are created from the folding of the upper layers of earth's crust. valleys on the other hand are made from the erosion of land or soil. tectonic uplift of the earths crust is also responsible for creating mountains.
The crab nebula consists of an oval-shaped mas of the filaments and they are imprints of the progenitor star that surrounds the diffused blue region and is helium-rich, other than gold other elements like the iron, oxygen and the uranium are produced.
