1) in a stagnant reservoir, dead organic matter settling to the bottom does not have time to decompose due to lack of oxygen for decomposers
2) as a result, a thick layer of silt forms at the bottom, which increases the level of the bottom and is a good soil for some plants
3) as a result of the growth of such plants, the amount of non-rotting organic matter at the bottom grows even more and the reservoir becomes swamped
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.