The potato was the first vegetable to be grown in space.
Why it is true
In nineteen ninety-five, aboard the Space Shuttle Columbia, scientists successfully grew potatoes, testing the viability of crops on long-duration missions.
Source: NASA Space Agriculture
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.