Here are four excretory products and the organs that produce them:

1. Urea: Produced by the liver as a byproduct of protein metabolism and excreted by the kidneys.

2. Carbon dioxide (CO2): Produced by cells during cellular respiration and excreted by the lungs.

3. Sweat: A combination of water, salts, and urea produced by sweat glands in the skin.

4. Feces: Undigested food and waste products produced by the digestive system and excreted by the rectum.