What are cells, and what do they do?

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C. Temperatures in the tundra range from extreme highs to extreme lows.

During the winter a Tundra can reach temperatures of -50 degrees. In the summer a Tundra usually reaches a max of only 45 degrees. A Tundra is pretty much cold during the summer and freezing during the winter. So, therefore, the answer must be C because a Tundra never gets extreme highs in temperature. 

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