1.Fish gills are organs that allow fish to breathe underwater. Most fish exchange gases like oxygen and carbon dioxide using gills either on side of the pharynx.
2.Gills are branching organs located on the side of fish heads that have many, many small blood vessels called capillaries.
3.The colour is red
4. A Gill filaments project from each arc between the dorsal upper and ventral lower surfaces of the filaments.
Explanation:
A rock falling through Earth's atmosphere from outer space is called a asteroid
Pollution can come from both natural sources and human activities depending on the type of pollutant.
<h3>What is pollution?</h3>
It is the release of substances into the environment to the extent that the well-being of plants, animals, and humans starts getting affected.
Substances that are released into the environment to the extent that they start affecting the organisms in the environment negatively are known as pollutants.
Pollutants can come from natural sources or as a result of human activities.
For example pollutants such as oxides of sulfur, methane, carbon dioxide, etc. can come from natural processes such as volcanic eruptions, activities of microbes, etc.
Pollutants such as oxides of carbon and sulfur can also be generated as a result of human activities such as the burning of coal, technological inventions, etc.
More on pollution can be found here: brainly.com/question/23857736
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