Answer:
1. primary source materials.
2. historiography
Explanation:
The use of slaves was reduced, because immigrants could fulfill the same roles as slaves in factories.
Answer:
Explanation: Yellow journalism was a style of newspaper reporting that emphasized sensationalism over facts. During its heyday in the late 19th century it was one of many factors that helped push the United States and Spain into war in Cuba and the Philippines, leading to the acquisition of overseas territory by the United States.
Answer:
The standard atomic weight is the average mass of an element in atomic mass units. Though individual atoms always have an integer number of atomic mass units, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element.