Fish filter water primarily through their gills, which are specialized organs designed for gas exchange.
Here's a breakdown of the process:
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Water Intake: Fish take water into their mouths by opening and closing their mouths.
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Gill Filtration: The water then flows over the gills. Gills contain numerous feathery filaments. These filaments are made of protein molecules and resemble tiny bristles.
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Gas Exchange: As water passes over the filaments, oxygen is extracted from the water and carbon dioxide is released. This is the primary function of the gills.
Therefore, the water is filtered through the gills in the sense that oxygen is extracted from it as it passes through. The gill structure also helps to remove particulate matter from the water, although this is not the primary purpose.
