Which of these is an example of a freshwater source?

A river is an example of a freshwater source because it consists of water that has low concentrations of dissolved salts compared to seawater, making it suitable for various organisms and ecosystems. Freshwater sources like rivers play a crucial role in the water cycle. They collect water from precipitation and runoff, providing habitats for numerous species, supporting biodiversity, and serving human needs for drinking water, agriculture, and recreation.

In contrast, oceans and seas are saline bodies of water with much higher salt content and are classified as marine environments. Deserts, while they can store and have limited amounts of freshwater, are primarily defined by their dry conditions and lack of large water bodies, thus not qualifying as freshwater sources on their own.