Final answer:
An industry's smokestack is considered a point source of pollution, which is a single identifiable source that emits pollutants directly into the environment.
Step-by-step explanation:
An industry's smokestack is an example of a point source of pollution. Point-source pollution refers to contamination of the environment that occurs when pollutants are emitted from a single, identifiable location, such as a smokestack. This differs from nonpoint-source pollution, which comes from multiple and diffuse sources. Stationary sources, like a smokestack, are fixed facilities from which pollutants are emitted, and they can be a significant contributor to air quality issues. Industries often have to install emission control equipment to manage and reduce the release of these pollutants into the atmosphere.