"Do you have a ruler?"
This 'も' is part of the word 'もっています' and is not a ’postpositional particle’.
'もっています' means 'have' in this sentence.
So it is necessary in this sentence.
Small hiragana is not become the first letter of a word. (Except for be new Japanese words be made by high school's girls)
'っています' is not exist as a word.
There are no spaces in Japanese, and line breaks can happen between any pair of characters, so the "word tiles" only exist as a crutch / teaching tool. If you're going to read / write in a fashion intended for native Japanese, you need to order individual characters. Breaking up "words" helps you practice that.