<human>: What does a colonoscopy involve?
<bot>: A colonoscopy involves inserting an endoscope into the rectum and passing it through the entire length of the large intestine. The scope has a light source, camera, and other instruments that allow the doctor to examine the lining of the colon for any abnormalities or polyps. After examining the colon, the doctor may take biopsies, remove polyps, or perform other procedures as needed.