photography detects colors and wavelengths of light that people cannot normally see.

Gold is not now being extracted from seawater. why not? a. it would be too disruptive to marine life to develop any marine mineral resources b. there is no gold in seawater c. we don't know how to extract minerals from seawater d. it would be too costly and difficult to separate the small amount of gold from the very large amounts of halite and other minerals

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.

The dashed segment of the plotted experiment in the graph in the lesson is called an