Fish have gills why ?

Fish have gills because they are aquatic animals that need to extract oxygen from water in order to survive. Gills are specialized organs that allow fish to extract oxygen from water and release carbon dioxide. This process is essential for their respiration and helps them to breathe underwater. Gills are highly efficient at extracting oxygen from water, allowing fish to thrive in their aquatic environments.

Fish have gills because they need to extract oxygen from water to survive. Water contains dissolved oxygen, but it is not in the same form as the oxygen in the air that humans and other land-dwelling animals breathe. Gills are specialized organs that allow fish to extract oxygen from water and use it for respiration.

Gills are made up of thin, delicate filaments that are covered in a mucus layer. The mucus layer helps to trap oxygen molecules from the water. The filaments are also lined with blood vessels, which allow the oxygen to be absorbed into the bloodstream.

When a fish breathes, it takes in water through its mouth. The water passes over the gills, where the oxygen is absorbed into the bloodstream. The deoxygenated water is then expelled through the fish's gills slits.

Gills are very efficient at extracting oxygen from water. However, they are only able to function in water that contains a certain amount of dissolved oxygen. If the water contains too little oxygen, the fish will not be able to get enough oxygen to survive.