https://www.khanacademy.org/science/karnataka-bridge-course-class-7th-science/x23f4b0ee108f5758:water/x23f4b0ee108f5758:properties-of-water/e/need-utility-and-sources-of-water 2025-08-05T08:33:57.588913915Z Need, utility and sources of water LO1: Need and utility of water. LO2: sources of water Revathi exercise