A river is a natural water stream flowing in the channel developed by it and feeding on the surface and underground runoff from its basin. A lake is a natural or artificially created body of water, filled within the lake bed with water and not directly connected to the sea. A swamp is a land area characterized by excessive moisture, increased acidity and low soil fertility, with the release of stagnant or flowing groundwater to the surface, but without a permanent layer of water on the surface.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.