What Am I Riddles

Question: I open to close but I close to open.
I'm surrounded by water but I'm never soaking.

What am I?

Question: Everyone has me but nobody can lose me.What am I?

Question: You use me from your head to your toes,
the more I work the thinner I grow.

What am I?

Question: I go up and I go down,
towards the sky and the ground.
I'm present and past tense too,
Let's go for a ride, me and you.

What am I?

Question: what comes in hard comes out soft and you blow ???????????????????????????????????????/