A strand of spider silk is stronger than steel of the same thickness.
Why it is true
The silk protein has a molecular structure that gives it extraordinary tensile strength. It is also very elastic, able to stretch significantly before breaking.
Source: Material Science 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.