Dental x-ray film is surrounded by a sheet of white paper inside the film packet

A ______ communications system allows simultaneous two-way communications by using two frequencies for each channel

a. simplex b. duplex c. multiplex d. trunking

You are called to a residential neighborhood at 12:30 A.M. Your patient has just finished eating a super-sized meal of deep fried fish. He is now complaining of a "crampy" pain in the right upper quadrant and has had two episodes of nausea and vomiting with a green emesis. What condition do you suspect that your patient is experiencing?

A) Intestinal obstruction B) Peptic ulcer C) Appendicitis D) Cholecystitis