Acronym Soup: PKOC?

Questions

---------- is the scent on the artificial rabbit that is used in greyhound races.?

Australian Rules football was originally designed to give ---------- something to play during the off season.?

Dartboards are made out of ---------- hairs.?

Four men in the history of boxing have been knocked out in the first ---------- seconds of the first round.?

In 1936, American track star Jesse Owens beat a ---------- over a 100-yard course. The horse was given a head start.?