Answer:
What is used to yell in a text?
What is used by man, tossed by trees, everywhere but unseen?
I occur twice in eternity. And I'm always within sight.
What Can Fly Without Wings
I call the trees my home, yet I never go inside, and if I ever fall off the tree I will be surely be dead.
You can always see it, but it's too far away to touch. Mountains rest on it, and at sea it surrounds you. What is it?