<span>Definition of uniformitarianism. :a geological doctrine that processes acting in the same manner as at present and over long spans of time are sufficient to account for all current geological features and all past geological changes — compare catastrophism.</span><span>
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Answer: Page 350
Explanation:
Check page 350 of the text, I think that should help.
Approximately about 25% <span>of the Sahara Desert is covered by sand sheets and dunes. The correct option among all the options that are given in the question is the second option. The other choices are incorrect and can be neglected. I hope that this is the answer that has actually come to your help.</span>