What Am I Riddles

Question: No matter how hard you try,
I can open what you can't.
If it wasn't for me,
on your front porch you would stand.

What am I?

Question: I am a cave full of bones,
and the house of a worm.

What am I?

Question: I turn polar bears white
and I will make you cry.
I make guys have to pee
and girls comb their hair.
I make celebrities look stupid
and normal people look like celebrities.
I turn pancakes brown
and make your champagne bubble.
If you squeeze me, I'll pop.
If you look at me, you'll pop.

Can you answer the riddle?

Question: I wasn't born a horse,
and I never fly.
Yet sometimes I still soar,
right into the sky.
I often contain breath,
and yet I never die.
Sometimes I am torn,
but I never sigh.
Often, with ambition, I aspire,
and go till I can go no higher.
Then, like many men, so great,
I sink into a low state.
What am I?

Question: What is red and white at home, but can never be that when it leaves?