Human stomach acid is strong enough to dissolve razor blades.
Why it is true
The pH of gastric acid is very low, allowing it to corrode metals like zinc and even certain blades, though it should not be tested.
Source: Medical Journal
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.