No one knew for certain the reason for the explosion. APEX
I can only answer some of these but
3 - Harriet Beecher
4 - Popular Sovereignty
^ These are confirmed, I'm sure of it
Now, I'll assume on these ones
2 - Bleeding Kansas
1 - Wilmot Proviso
5 - Fugitive Slave Act
I apologize if I'm wrong on these
The USSR’s help in defeating Japan. The US wanted Stalin to attack from above during the invasion of Japan, aka Operation August Storm. This happened with the Soviet invasion of Manchuria.
House Un-American Activities Committee
The Executive branch must receive approval from "the Senate" when appointing heads of executive departments, ambassadors, and Federal Court Judges, since this is one of the most important examples of the system of "checks and balances" that exists in the US.
