This depends entirely on the research project in question. For instance, if you want to learn more about how the memorial was constructed, you could look at the history of its architecture, etc. Or if you want to know more about how it was conceived you should look at the debates surrounding it's creation.
Answer:
The act was one of the most controversial element of the 1850 compromise and heightened Northern fears of a slave power conspiracy.It require that all the escaped slave,upon capture, be return to their masters
On April 17, 1961, 1400 Cuban exiles launched what became a botched invasion at the Bay of Pigs on the south coast of Cuba. In 1959, Fidel Castro came to power in an armed revolt that overthrew Cuban dictator Fulgencio Batista.
That the neutron had split the uranium atom into lighter atoms and converted some of its mass energy
The answers should be:
1: 3
2: 67
3: 43
4: 37
Sorry if these are not correct.