One of Lincoln's greatest achievements was (A) Building more factories in the North
(B) Selling cotton to Europe, and thus bringing money to the south.
(C) Starting the Social Security system.
(D) Preserving the United States of America

(D) Preserving the United States of America

Explanation:

He managed to keep the United States together though a Civil Way had to happen in order for differences to be sorted out

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the answer that best explains what happened to george washington at fort necessity, pennsylvania is : washington was attacked by the french but was able to negotiate with them to peacefully end fighting. the battle took place on july 3, 1754. the battle is considered as being the start of the french and indian war.