How many sides does a circle have?

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

I have no life, but I can die. What am I?

How many times can you subtract the number two from the number fifty?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

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?

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

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

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

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?