Living organisms participate in the movement of substances, so the circulation of substances is biogenic. Producers synthesize organic substances, some of which are passed on to the consumers along the food chain, and some remain unused. A certain amount of organic matter of producers and consumers is returned to the soil with cadaveric material, excrement (detritus). As a result of the activity of reducers, they turn into minerals, involved by producers in a new cycle.
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.