I know, because the first time I took it; it said I only got 86%, so I went back and looked at the three I thought they had wrong, I changed the answer to the ones I thought they wanted to hear; and I got 100%.
Also, they figured their percentages wrong; or rather they more likely rounded improperly, which is a common programming mistake.
I'll give you one of them: Yes, in fact Columbuses ships DID land in North America in 1492. They landed in the Carribbean, then Hispaniola and Cuba, in October of 1492. All of those places are by traditional continental grouping, in North America; unless you take the communist revisionist position that Hispaniola, Haiti, and Cuba are not in North America, but in fact are either their own special area, or are part of South America (to set them up in opposition to American interests).
Yes, I'm aware that geologically those islands are not part of the North American plate; however for 400 years before we figured that out, the islands were included in NA; and politically should be.