1. The Core: What is it made up of? nickel and iron silver and copper gas mercury

2. Mantle: What's the lower limit of the mantle? 3700 km 2100 km 1300 km 2900 km

3. Asthenosphere: What is its major role? it protects Earth from earthquakes it supports the Earth's crust it is rich in minerals it generates heat

4. Lithosphere: What does "lithos" mean in Greek? layer hot hard rock

5. The Crust: What discontinuity delimits it from the mantle? Jeffreys Gutenberg Repetti Mohorovicic

6. Hydrosphere: Which of the following is not a part of the hydrosphere? underground water they are all components of the hydrosphere glaciers water vapors

7. Biosphere: Which of the following does not belong to it? plants the soil animals fungi

8. Atmosphere: What percent of the atmosphere is made up of nitrogen and oxygen? 85% 95% 90% 99%

9. Homosphere: According to what criterion is the atmosphere divided into the homosphere and the heterosphere? composition temperature mass density

10. Heterosphere: At what approximate height does this layer start? 15 km 80 km 40 km 55 km

11. Troposphere: What percent of the atmospheric mass is concentrated in this region? 90% 70% 50% 99%

12. Stratosphere: Which type of radiation can get through the ozone layer situated within this atmospheric region? ultraviolet radiations cosmic radiations Roentgen radiations infrared radiations

13. Mesosphere: Which of the following can be associated with this layer? auroras burning meteors the ozone layer solar winds

14. Thermosphere: What is this layer also known as? Ionosphere Cryosphere Magnetosphere Antroposphere

15. Exosphere: Which of the following is true about this outermost atmospheric layer? it concentrate 10% of the atmospheric mass satellites orbit in this layer radio waves are reflected back to Earth from this layer its temperature is higher than the thermosphere's