The correct option is 4: Gills Marine bony fish, known as teleosts, face a significant challenge in their hypertonic (saltier) environment: they constantly lose water to the sea by osmosis across their permeable membranes, primarily the gills. To counteract this constant dehydration, the fish must continuously drink seawater. However, drinking seawater introduces a massive load of salt into their bodies, which must be actively removed to maintain a stable internal…Read More