On the top of Mount Everest, the total atmospheric pressure is reduced to 33.73 kPa (about one-third of its value at sea level).
Assume that the fraction of the atmosphere that is made up of oxygen is the same at all elevations.
If the partial pressure of oxygen at sea level is 21 kPa, what is the partial pressure of oxygen on the top of Mount Everest?
A 12.73 kpa
B 11.2 kpa
C 54.73 kpa
D 7.0 kpa

Island arcs island arcs are long, curved chains of oceanic islands associated with seismic activity and mountain-building processes at certain plate boundaries. they occur where oceanic tectonic plates collide. along one side of these island arcs, there is usually a long, narrow deep-sea trench. at island arcs, the denser plate is subducted and is forced into the partially molten mantle under the less dense plate. the islands are composed of the extrusive igneous rocks basalt and andesite. the basalt originates most likely from the plastic mantle. the andesite originates most likely from the melting of parts of the descending plate and sediments that had accumulated on its surface. which list identifies minerals present in andesite from the greatest percentage by volume to the least percentage by volume?