1. Fish extracts the oxygen from the water and expels water through the gills. Fish can survive in water only through the dissolved oxygen present in water.
2. Aquatic plants make use of dissolved carbon dioxide for photosynthesis.
3. Carbon dioxide dissolved in water reacts with limestone to form calcium bicarbonate.
4. Marine organisms such as snails, oysters, etc., extract calcium carbonate from calcium bicarbonate to build their shells.
