The map below shows the progress the Union army made each year of the war. Look at the map. Then complete the sentence below.

Which of the following inventions most directly allowed ancient farmers to produce a surplus ?

How was rockefeller able to build his monopoly across the oil industry? he found newer and cheaper ways to refine oil, increasing his profits. he confined his business to ohio so he could buy all the refineries there. he bought up oil refineries, cut costs, and reinvested his profits in other refineries. he began to sell kerosene as well as oil, expanding his market.

Before the civil war, the constitution protected slavery -true -false