Is urine the only waste product that humans excrete?
No, urine is not the only waste product that humans excrete. Humans also excrete waste solids as fecal matter, and waste gas - primarily carbon dioxide and water vapor.
Pretty much like every other mammal. Through our colon, which is attached to our anus. Our urine is passed through our bladder, through our ureters, down our urethra and out of our body. Standing up or sitting down, either way, it comes out. But humans excrete waste in a toilet and animals excrete waste in their surroundings.