Across
- 3. other organisms use sunlight to
- 5. mantle.
- 7. colourless, odourless unreactive gas that
- 8. the chemical element of atomic number 7,
- 12. a biological community of interacting
- 15. between two glacial periods.
- 17. The official procedure or system of rule
- 18. relating to a period of milder
- 20. about 78 percent of the earth's
- 21. the action of breathing.
Down
- 1. capital of Japan
- 2. a thick subsurface layer of soil that
- 4. and their physical
- 6. affairs of state or
- 9. year, occurring chiefly in polar regions
- 10. of the crust and
- 11. below freezing point throughout
- 13. occasions.
- 14. the process by which green plants and
- 16. any accumulation of unconsolidated debris
- 19. the rigid outer part of the earth,