Secondary sources would be valuable to a historian in order to provide
a) the sights and sounds of an event.
b) insights into the thoughts and feelings of participants in an event.
c) a more thorough analysis of the impact on history of an event.
d) an evaluation of opinions of people at an event.

it will be c cause i just did the quiz

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.

the monroe doctrine is the best known u.s. policy toward the western hemisphere. buried in a routine annual message delivered to congress by president james monroe in december 1823, the doctrine warns european nations that the united states would not tolerate further colonization or puppet monarchs.