The correct answers are A) four-field crop rotation and E) selective livestock breeding.
<em>The adoption of the four-field crop rotation and selective livestock breeding helped to increase the amount of food produced per unit area of farmland. </em>
Crop rotation was a great idea to better use the portions of lands destined to farming. People divide the same area to grow different types of crops in different seasons. If farmers grow the same crop for many years in a row it can cause the soil depletes nutrients. Rotating crops helps the soil to reduce erosion and increase fertility. Livestock breeding is the process where farmers breed animals such as cows, pig, chickens, and constantly reproduce them to have better production and trade their products.
Generally speaking, "A. the average election results of the President of the United States" would not be considered an example of geography's impact on history, since this has little do with with geography in the United States.
In 1887, Congress established a commission to regulate the railroads by passing "The Interstate Commerce Act", which was mainly intended to keep railroad companies from becoming monopolies.
In the past, the Democrats would have said this is true. Most still do, but the Republicans have placed more and more emphasis on individual rights -- and it has not been carried out in a way that is entirely beneficial.
