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 c. core b. mantle d. crust 13. which of the following is not one of three factors that control the balance of an ecosystem? a. producers c. consumers b. decomposers 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. c. oblate spheroid. b. approximate oval. d. perfect circle. 16. which of the following is a probable source of earths magnetic field? a. earths iron core c. the sun b. the moon d. earths tides 17. ecosystems respond to environmental change by a. revolving. c. returning to a balanced state. b. decomposing. d. dying out. 18. which of the following is not involved in the movement of matter and energy between reservoirs? a. nitrogen cycle c. phosphorus cycle b. earth cycle d. carbon cycle 19. all the following are important sources for energy in the earth system except a. water energy. c. internal convection. b. the sun. d. gravity. 20. who was the first to explain the effects of gravity in his law of gravitation? a. mohorovicic c. moho b. oikos d. isaac newton

Explanation:

Step1: Recall Earth's circumference fact

The average circumference of Earth is about 40,000 km.

Step2: Analyze compositional structure

The compositional structure of Earth includes crust, mantle and core. Global ocean is not part of the compositional structure.

Step3: Identify ecosystem - balance factors

Producers, consumers and decomposers control the balance of an ecosystem. Solar energy is not one of these three factors.

Step4: Know energy - transfer start

The transfer of energy throughout an ecosystem begins with plants capturing solar energy through photosynthesis.

Step5: Recall Earth's shape

The shape of Earth most closely resembles an oblate spheroid.

Step6: Identify magnetic - field source

A probable source of Earth's magnetic field is Earth's iron core.

Step7: Understand ecosystem response

Ecosystems respond to environmental change by returning to a balanced state.

Step8: Analyze matter - energy movement

There is no "Earth cycle" involved in the movement of matter and energy between reservoirs. The nitrogen, phosphorus and carbon cycles are involved.

Step9: Identify energy sources

Water energy, the sun and internal convection are important sources for energy in the Earth system. Gravity is not an energy - source in the same sense.

Step10: Recall gravity - law discoverer

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