Answer: 3, 4
Explanation:
3) The United States gave up claims to Texas
4) Spain gave Florida to the United States
During the Civil War, Kentucky was a border state, but they on the south's side "team" (they had slaves and wanted to keep them). During this war, the north and south had a war, known as the Civil War. Abraham Lincoln wanted Kentucky on his side, the north side. Kentucky was a border state, therefore he wanted it to be on the north's side since it wasn't completely in the south. I believe he says he must have Kentucky because it's another state on his side to help with this war, if that makes sense.
Between russia and Ukraine......probably
A - Because they are a direct link to the events in history
Primary sources are sources that came from that time of history from the same location, time period, and era. For instance, journals from World War II from a French Military leader. These are direct links to that time in history and are the most accurate sources that are presented.
B is incorrect as even without these sources there are other methods to know about history such as secondary sources.
C is incorrect as primary sources are not the only way - again, secondary sources are a thing.
D is incorrect as secondary sources are reliable and can be trusted, but they just aren't as important and well, direct as primary sources.
Hope this helps!