Answer:
D. cars, people, factories, animals
Explanation:
Pollution is the introduction of substances or other physical elements in a medium that cause it to be unsafe or unfit for use.The medium can be an ecosystem, a physical environment or a living being. The pollutant can be a chemical, energy (such as sound, heat, light or radioactivity). It is always a negative alteration of the natural state of the environment, and generally, it is generated as a consequence of human activity considering it a form of environmental impact.
Pollution can be classified according to the type of source from which it comes, or by the form of pollutant that emits or means that pollutes. There are many pollutants among them chemicals (such as pesticides, cyanide, herbicides and others.), Urban waste, oil, or ionizing radiation. All these can cause diseases, damage to ecosystems or the environment. In addition, there are many gaseous pollutants that play an important role in different atmospheric phenomena, such as the generation of acid rain, the weakening of the ozone layer, and climate change.
