What does this below rebus puzzle mean?

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

81 x 9 = 801. What must you do to make the this equation true?

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

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"

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

A thief enters a store and threatens the clerk, forcing her to open the safe. The clerk says, “The code for the safe is different every day, and if you hurt me you’ll never get the code.” But the thief manages to guess the code on his own. How did he do it?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?

Can anyone tell me a word in the English dictionary which has a silent 'z'?