The Riddle of Winds
For the second trial they bring you to the top of the tallest tower, where the four winds themselves come when they're called — you can't see them, but you can feel them arrive, one cold, one warm, one wet, one smelling of far-off deserts.
It's the cold one that speaks, in a voice like a keyhole. “Little champion. Answer once, and only once.”
“We carry ships and bend the oak. We lift the eagle past the peak. Yet there's one small thing all four of us together cannot hold for longer than a moment, though every living creature gives it away all day. What is it?”
The winds curl around the tower, waiting. Sera stands at the stair with her eyes shut — she is not allowed to help, and shutting her eyes is apparently how hard she is not-helping.
One answer, Madison.