How can one talk without saying a single word?

Replace the question mark in the picture below.

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

A man is found hanging dead from the ceiling of a room. The room’s dimensions are 15 x 15 x 15. The man is only 6ft tall and the rope was only 2ft long. There are no windows and only one door to the room. The door is bolted shut from the inside, and a puddle of water is under the man. How did he kill himself?

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

A finger goes in me. You fiddle with me when you're bored. The best man always has me first. What am I?

Buy me, smell me or deliver me, I do not change.

Who am I?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

A man is found dead with a knife in his back When the investigation is done. A chair lays beside him and the forensic team finds moisture around the body.

If he committed suicide, how did he do it?