Gill

Real World Example

Imagine trying to breathe under a thick blanket that covers your entire face; it's challenging because you're not getting enough air. Similarly, aquatic animals face a problem when trying to extract oxygen from water, which is not as straightforward as breathing air. Just as you would need a special way to filter out air through that blanket, gills function as intricate filters that allow fish to extract oxygen from water efficiently, acting like specialized, natural sieves for oxygen.