Waterfall. <span>As the river or stream wears away the weak rocks, they travel across the surface of stronger rocks. These more resistant rocks become the capstones to waterfalls. The number and thickness of these stronger rock units in a vertical sequence of rocks controls how many water falls there are and how much vertical drop there is on each waterfall.</span>
I think the answer is B... but I’m not sure.
The answer is a
hope this helps
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The answer to the question given is:
<span>better mass production techniques
</span>Better mass production techniques BEST explains the increased totals for all cars made in the 1920s. Henry Ford, together with <span>General Motors and Chrysler emerging as the “Big Three” auto companies, </span> innovated mass-production techniques that became standard, by the 1920s.