The document discusses the hydrosphere and biosphere. The hydrosphere includes all water on Earth's surface and near-surface, such as oceans, lakes, rivers, ice caps, and groundwater. The hydrologic cycle involves evaporation, condensation, precipitation, and runoff of water. Most water is ocean water, which has high salt content, while a small percentage is freshwater found in ice caps, surface water, and groundwater aquifers. The biosphere is the thin layer at Earth's surface that supports life through resources like sunlight, water, and moderate temperatures.