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

I know a nine-letter word having only one vowel.
Do you ?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

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?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?

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

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?

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