Suppose you are on a hike when you find a dark-colored igneous rock (pictured below). the rock has very small crystals that can only be seen under magnification. you bring the rock back to the lab and make a thin section of it so that you can examine its mineral composition using a petrographic microscope. in thin section, you are able to determine that the rock consists of plagioclase feldspar (mostly ca-rich) and several ferromagnesian minerals. what does this tell you about the rock's origin?

If you could drill a hole straight to the center of the earth, and keep track of what the hole is going through, youwould find: a) you would go through one sort of material, and then a different, denser material, and then a still-different, still-denser material, because the planet is made of concentric layers, sort of like an onion.b) you would go through one sort of material all the way to the center, because the planet is all mixed up.c) if your hole started at the north pole, you would go through different layers of different materials, but ifyour hole started at the equator, you would go through one sort of material all the way to the center.d) if your hole started at the equator, you would go through different layers of different materials, but if yourhole started at the north pole, you would go through one sort of material all the way to the center.e) you would strike diet pepsi when you got to the center.

Aplane cuts a pyramid as shown in the diagram. what is the shape of the cross section? a. a hexagon b. a pentagon c. a square d. a triangle

Which of teh following would explain the importance of the trans-siberian railroad to russia's economy? (schoology test)