The speaker adverted the students attention to his PowerPoint presentation.

"Advert" is a regular verb; therefore, "adverted" is its past participle.

this a lead that provides d reader with quotes, it can b thus:'

it is said that when ppreparation meets opportunity failure is adverted''

Nothing. I suppose you are asking about the Compromise of 1850, but that was signed by Millard Fillmore( Taylor had died)

Possibly, but not necessarily. In history there are many alternate endings which result from alternate decisions, but we can never know them for certain as those decisions were never made.