endsoz
twelve
A word. Many groups of letters is called a sentence(:
The answer to your riddle is "stairs." Stairs allow people to go up and down between levels, yet they themselves remain stationary. The word "stairs" consists of six letters.
Mailbox
Queue. Take away the four letters UEUE and you are left with Q.
dozens
There is no twelve letter word spelled with the letters 'ntrarxetisan'.
Twelve has six letters, seventeen has nine.
twelve
considerably
The letters in "remain" can also be used to spell "marine" or "airmen".
sixty-twelve
battlefields
Dozens. Take s away and you have dozen.
You are asking us to construct a seven letter word, using twelve letters. This does not seem to be mathematically possible.
There isn't a twelve letter word, but if you add another letter "n" you get: entertain met (add letter "n") entertainment
Dozens