What effects do the sources available to a historian have on the ways she or he understands the past

There are two kinds of sources, primary and secondary.
primary sources are sources directly from the time period, such as diary entries and artifacts.
secondary sources are sources that get information from primary sources and use them to analyze data, such as biographies and encyclopedias 

The electoral college consists of 538 electors. a majority of 270 electoral votes is required to elect  the president. your state's entitled allotment of electors equals the number of members in its congressional delegation: one for each member in the house of representatives plus two for yoursenators.congress does the electoral college represent