Chuck was on a Greyhound bus that pulled into a rest stop. After all of the passengers had exited the bus to buy refreshments, stretch their legs, and do other things, Officer Green boarded the bus with Buff, a trained drug detection dog, and performed a drug sweep. The sweep consisted of removing all bags located in overhead compartments, placing them on the seat below, and having Buff sniff them. Buff alerted to a maroon bag. Green put all the bags back in the overhead compartments before the passengers returned to the bus and, after they reboarded, inquired whether any of them owned a maroon bag. When no one claimed the maroon bag, Officer Green removed it from the bus, opened it, and examined the contents. On discovering 24 grams of crack cocaine, along with a driver's license with Chuck's picture on it, he reboarded the bus and arrested Chuck. At his trial for possession of cocaine, Chuck moved to suppress the evidence on the grounds that it was obtained through an illegal search and seizure.

(1) Did Officer Green's removal of Chuck's bag from the overhead compartment and putting it on the seat below constitute a seizure within the meaning of the Fourth Amendment?

(2) Did exposing Chuck's bag to an examination by Buff constitute a search?

(3) Did Officer Green's removal of Chuck's bag from the bus when no one claimed it constitute a seizure?

(4) Did Officer Green's subsequent opening of Chuck's bag and examining the contents constitute a search?