What does this rebus puzzle means ?

This is a simple one. You just have to count the number of Fs in the given sentence.

Finished Files are the result of years of scientific study combined with the experience of years.

How many did you count?

Why do you find that most of the buildings are deprived of the 13th floor?

Can you name an animal whose killing cannot be performed without spilling your own blood?

Can you find the mistake in the below statement?

Vin Diesel is pulling a theft and has planned to run away with all the cash kept in the safe. But the only way to open the safe is the 13 character password. He has a set of five clues given to him by a trustworthy source.

Exactly two of the below statements are false.
The password is contained within this sentence.
The password is not in this hint.
The password is within only one of these statements.
At least one of the above statements is a lie.

Prove that the below maths equation is true.

8 + 8 = 91

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

What happened when the wheel was invented?

I have branches, but no fruit, trunk or leaves. What am I?