On what basis can we judge that the plant is aging?

By many signs, one can judge that the plant is aging,
A more vivid expression of this, for example, an ordinary tree.
The lifespan can be found by counting its annual rings, in the context.



One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.