________ is the invasion of the body by a pathogenic microorganism

A young male patient has been involved in a motor vehicle accident. As an unrestrained driver, his head went through the driver's side window; in the process a portion of his ear was severed. Blood is now coming from the remaining portion of his left ear. In overseeing the care of this patient, which of the following would require corrective action?

A) A loose dressing placed over the left ear B) Rolled gauze in the ear canal C) The severed ear wrapped in saline-soaked gauze D) Transport immobilized in a supine position

P waves usually appear before:

A) upright waves. B) QRS complexes. C) PR intervals. D) T waves.