Ice Age

4. a vast, flat, treeless Arctic region of Europe, Asia, and North America in which the subsoil is permanently frozen.
6. an extended mass of ice formed from snow falling and accumulating over the years and moving very slowly.
8. of or relating to the nature of a continent.
9. too poor to produce much or any vegetation.
12. ice sheets a mass of glacial land ice extending more than 50,000 square kilometers.
14. a measure of the warmth or coldness of an object or substance with reference to some standard value.
19. a scientist who specializes in the study of life forms that existed in previous geologic periods, as represented by their fossils.
20. a detached and rounded or worn rock, especially a large one.
21. glaciers form in high mountains and travel through valleys.
22. no longer in existence.

1. a specialist in the science or branch of biology dealing with animals.
2. the branch of zoology dealing with fishes.
3. the action of becoming larger or more extensive.
5. an elongated depression between uplands, hills, or mountains, especially one following the course of a stream.
7. a large naturally occurring community of flora and fauna occupying a major habitat.
10. the gaseous envelope surrounding the earth; the air.
11. dioxide a colorless, odorless, incombustible gas, CO2, present in the atmosphere.
13. the amount by which something is reduced or diminished.
15. to cause to lean, incline, slope, or slant.
16. surface the part of Earth we interact with.
17. a person who specializes in research and study of the science of the earth’s dynamics and physical history, the rocks of which it is composed, and the physical, chemical, and biological changes that the earth has undergone or is undergoing.
18. mammoth a shaggy-coated mammoth that lived in cold regions across Eurasia and North America during the Ice Age.