09.1 System and structure of the Earth

4. The outermost atmospheric layer with extremely thin air where satellites orbit.
5. The twilight ocean zone receiving a small amount of light, extending from 201 meters to 1 kilometer in depth.
8. The middle layer of the Earth existing in semi-solid and solid states rich in silicon and iron.
12. Space rocks that burn up due to friction upon entering the mesosphere.
15. A region within the stratosphere that absorbs harmful ultraviolet radiation from the sun.
17. The height measured from sea level that affects atmospheric temperature and air pressure.
19. The solid ground layer of the Earth divided into the crust, mantle, and core.
20. The atmospheric boundary layer located between the stratosphere and mesosphere.
21. A physical force per unit area that decreases with higher altitude and increases with ocean depth.
23. The atmospheric boundary layer located between the mesosphere and thermosphere.
26. The frozen water component of the Earth system including ice and glaciers.
28. The innermost center layer of the Earth divided into an outer molten layer and inner solid layer.
29. A layer within the thermosphere containing charged particles that reflect radio signals.
30. The atmospheric layer above the troposphere containing the ozone layer.

1. The water component of the Earth including oceans, lakes, rivers, and groundwater.
2. The atmospheric boundary layer located between the thermosphere and exosphere.
3. The rigid outer layer of the Earth consisting of the crust and top part of the mantle.
6. The middle atmospheric layer that is the coldest and burns up meteoroids.
7. A measure of heat that varies across different atmospheric layers and ocean depths.
9. A layer of air surrounding the Earth.
10. The life zone of the Earth consisting of a variety of living organisms.
11. The atmospheric boundary layer located between the troposphere and stratosphere.
13. The light generated by deep-sea organisms in the aphotic zone to see and hunt.
14. The upper viscous semi-solid layer of the mantle on which tectonic plates float.
16. Colorful light displays formed by charged particles/ions in the thermosphere layer.
18. The lowest and densest atmospheric layer closest to Earth where weather changes occur.
22. The hot atmospheric layer containing ions where auroras are formed.
24. The dark ocean layer from 1 to 6 kilometers in depth where sunlight cannot reach.
25. The sunlit top layer of the ocean extending from 0 to 200 meters in depth.
27. The outermost and thinnest solid layer of the Earth formed by rocks, soil, and minerals.