This test is a bit dubbious. Some of the answers are in contradiction to what Wikipedia or other sources say, or are badly formulated.
There may not be evidence that Marco Polo brought back ice cream (or tales of it) to Europe, but I don't think there is any proof that he didn't either. Why ask a question when nobody knows the answer ?
Before 1492, most ordinnary European people (not great thinkers or even navigators, of course) did believe that the earth was flat because the Bible said so. Again, it depends what one calls "flat". The Norse representation of the world could be called "flat" although it was like a 3-D tree carrying a more or less "flat" world, so it wasn't really flat.
As for the Dutch purchasing Manhattan, it was in fact a Walloon who did (Pierre Minuit). I know that there was no state called Wallonia or Belgium at the time, but I still find it wrong to call him "Dutch".
Whereas they lack accuracy for such questions, I got it wrong for the lake, as I thought the meaning of the translation was close enough.
Got most right though.