The anus is the external opening of the rectum that is the last part of the gastrointestinal tract. It is situated in the posterior aspect of the perineal area between the coccyx and the pubic symphysis. Its main function is to keep the contents of the rectum (your solid waste) from leaving the body until it is convenient to do so. It's color is a light brown.
The rectum. And you can tell it comes first by just looking at a model of the digestive system. The anus is at the tip of your rectum, so the rectum would come first, and the anus would come last. :) :) :) :) The rectum comes first. The rectum is the final straight portion of the large intestine in some mammals, and the gut in others, terminating in the anus.