Which of the following is an example of a bodily fluid?

Urine is considered a bodily fluid because it is produced by the body's metabolic processes and is released as a waste product. Bodily fluids are any liquids that are produced by the body, which include not only urine but also blood, saliva, sweat, and other secretions. Being a direct product of the body, urine plays a significant role in various physiological processes and is essential for maintaining the body's internal environment. The other options—air, dust, and food waste—do not fall under this category. Air is a gas necessary for respiration, dust is a collection of tiny particles that can accumulate in the environment, and food waste is a byproduct of digestion but not a fluid produced by the body itself. Thus, urine distinctly qualifies as a bodily fluid.