It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

If you say my name, I will no longer exist. What am I?

I don't get anymore wetter, no matter how much rain falls on me.

What is more useful when it is broken?

What has many keys but can’t open a single lock?

I am the fastest animal but cannot climb the tree. What am I?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

The dirtier I get, the whiter I look. Who am I?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?