B. because the work in one area and are specialized to do that work.
Japan's Reaction Despite the horror of Hiroshima, there were many in the Japanese government that disbelieved the United States had the technical ability to develop, yet alone transport and drop, an atomic bomb. The events of August 9 changed all that.
Explanation:
D. mound builders
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In August 1896 _________ was found in a tributary of the Klondike River in Canada's Yukon Territory.
Copper
I think the answer is gold :)