Question

1. which of the following is closest to the average circumference of earth? a. 4,000 km b. 40,000 km c. 7,400 km d. 74,000 km 12. which of the following is not part of the compositional structure of earth? a. global ocean b. mantle c. core d. crust 13. which of the following is not one of three factors that control the balance of an ecosystem? a. producers b. decomposers c. consumers d. solar energy 14. how does the transfer of energy throughout an ecosystem begin? a. humans create pollution. b. plants capture solar energy through photosynthesis. c. the energy store on earth is depleted. d. producers eat consumers. 15. the shape of earth most closely resembles a(n) a. perfect sphere. b. approximate oval. c. oblate spheroid. d. perfect circle. 16. which of the following is a probable source of earths magnetic field? a. earths iron core b. the moon c. the sun d. earths tides 17. ecosystems respond to environmental change by a. revolving. b. decomposing. c. returning to a balanced state. d. dying out. 18. which of the following is not involved in the movement of matter and energy between reservoirs? a. nitrogen cycle b. earth cycle c. phosphorus cycle d. carbon cycle 19. all the following are important sources for energy in the earth system except a. water energy. b. the sun. c. internal convection. d. gravity. 20. who was the first to explain the effects of gravity in his law of gravitation? a. mohorovicic b. oikos c. moho d. isaac newton

Explanation:

1. The average circumference of the Earth is about 40,000 km.
2. The global ocean is not part of the compositional structure of the Earth in terms of internal layers; the main compositional - structure layers are crust, mantle, and core.
3. Producers, consumers, and decomposers are the biotic factors that control the balance of an ecosystem, while solar energy is an abiotic factor but not one of the three main biotic - controlling factors.
4. The transfer of energy in an ecosystem begins with plants capturing solar energy through photosynthesis.
5. The shape of the Earth is an oblate spheroid, which is slightly flattened at the poles and bulges at the equator.
6. Earth's iron core is a probable source of Earth's magnetic field due to the movement of molten iron creating electric currents.
7. Ecosystems respond to environmental change by returning to a balanced state (homeostasis).
8. There is no "Earth cycle" in the context of matter - and - energy movement between reservoirs; the nitrogen, phosphorus, and carbon cycles are well - known.
9. Gravity is not a direct source of energy in the Earth system like water energy, the sun, and internal convection.
10. Isaac Newton was the first to explain the effects of gravity in his law of gravitation.

Answer:

1. b. 40,000 km
2. a. global ocean
3. d. solar energy
4. b. Plants capture solar energy through photosynthesis.
5. c. oblate spheroid
6. a. Earth's iron core
7. c. returning to a balanced state
8. b. Earth cycle
9. d. gravity
10. d. Isaac Newton