Gather in the forest and put in sealed jars pieces of bark and wood from weakly destroyed and, separately, badly destroyed dead trees. Place the jars in a warm room, adding two tablespoons of water to each. Observe the development of the mushrooms (after completing the observation, discard the mushrooms so as not to infect the wooden structures and furniture).
Parasitic fungi feed on organic substances produced by plants, dissolved in water, which move along the bark, and water along wood: In our experience in a jar with a weakly destroyed piece of wood, we will see the further development of fungi, because there is enough nutrients and water. And in the second bank, the tree is quite destroyed, there are few nutrients, so the development of mushrooms there either will not be there at all or it will be very weak.
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.