What is a depression in the ground due to a cave collapse or acidic water dissolution of limestone

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.

Which of the following events did not occur as a result of china’s open-door policy? a. trade between japan and china was encouraged. b. all countries were given equal access to chinese ports. c. foreign influence in china increased. d. the influence of the communist party weakened.

What is likely to happen in the long term if the earth continues to absorb more energy than it emits? a. the earth will discontinue recycling energy. b. organisms will begin to compensate for the change by incorporating more energy. c. the overall temperature of the earth will increase. d. the nutrient cycles will happen more frequently. select the best answer from the choices provided a b c d