What is harder to catch the faster you run?

Which tank will fill first?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

There is an English word that can be used up to four times in a row without modifying the spelling and form a valid grammatical sentence.

Do you know what word is that?

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

The more you take me, the more you leave me behind.
Who 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?

Replace the question mark with the number below given a simple math problem.

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?