What is the centre of gravity?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

There are forty elephants and they have forty-fore heads. How can this be possible?

What time is it when an elephant sits on a fence?

What is the last thing you take off before bed?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

Can you count the number of seconds in a year?

Clue: You need to bother about calculation.

Which city is three-fifths chick two third cat and 50% goat?

What 5-letter word typed in all capital letters can be read the same upside down?

Different lights make me strange by changing me into different sizes. What am I?