What is the difference between primary and secondary sources

When congress passed the way davis bill in response to lincolns reconstruction plans the president did what to the bill

War of 1812 allowed the us to take control of lake erie

How are the republican and democratic presidential candidates chosen? a. they are nominated by their state governments. b. each is nominated by his or her respective party. c. each is chosen by the governor of his or her home state. d. they are chosen by the house of representatives.