Answer:
What surrounds the world, yet dwells within a thimble?
Creatures of power, creatures of grade, creatures of beauty, creatures of strength. As for their lives, they set everything's pace. For all things must come to live. Under their emerald embraceย Either in their life or in their death.
This thing all things devours: Birds, beasts, trees, flowers; Gnaws iron, bites steel; Grinds hard stones to meal; Slays king, ruins town, And beats high mountains down.
They can be harbored, but few hold water. You can nurse them, but only by holding them against someone else. You can carry them, but not with your arms. You can bury them, but not in the earth.
I open wide and tight I shut, Sharp am I and paper-cut fingers too, so do take care, I'm good and bad, so best beware.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.