A patient is admitted with acute gastric ulcer with hemorrhage and perforation

The surgical first assistant's knowledge and skill level involves an understanding of

a. surgical anatomy and physiology. b. biochemical engineering. c. psychomotor kinesiology. d. advanced airway placement.

A plus sign (+) is used for _______________ codes, indicating procedures that are usually carried out in addition to another procedure. 

Fill in the blank(s) with the appropriate word(s).