The more of this there is, the less you see. What is it?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

I’m tall when I’m young, and I’m short when I’m old. What am I?

What have one eye but still cannot see?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?