Dissolved Oxygen (DO) is important for

Correct option is D

Dissolved Oxygen (DO) is crucial for maintaining the health of aquatic ecosystems, such as rivers, lakes, and streams. It is essential for the respiration of fish and other aquatic organisms. Low DO levels can lead to hypoxia, causing harm to aquatic life. Although DO is important for other water bodies like lakes and oceans, it is particularly critical in river systems where the flow and mixing of water affect oxygen levels.
Information Booster:
Drinking water – DO is not a critical factor in terms of human consumption. Water treatment plants maintain oxygen levels, but DO is more relevant for natural ecosystems.
Rainwater – DO in rainwater is generally low, and it mixes with water bodies where it plays a more important role.
Underground water – Groundwater often has low DO because it’s not exposed to atmospheric oxygen.