Inside me, you can see the surroundings and the sky. What am I, that keeps your plants warm and dry?

I get you in, without a key I get you out, if you're stuck I change your access for security I make multiple copies of items with teeth, so you don't have to rely on luck.

You put it in your mouth daily, and you keep it. You spit it you live, You swallow, you die.

When you go on a hike, put al your stuff in me, so you can walk around hands free.

One goes up, one goes down, trading places round and round. We never move from where we stay yet rise and fall in endless play.