Can you find the missing piece of the Porsche?

What breaks yet never falls, and what falls yet never breaks?

How many sides does a circle have?

What word begins and ends with an E, but has only one letter?

Three ants are going up a hill, one behind the other. The last ant then says to the other ants, 'There is an ant behind me!'' How come?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

Before Mount Everest was discovered, what was the highest mountain in the world?

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?