In many vertebrates, the majority of its existence is in an adult state. In many insects, the adult stage is the shortest and lasts only a few hours, necessary to leave offspring. In primitive animals, larvae live long, accumulating the necessary substances for reproduction. More developed animals live long in adulthood in order not only to leave offspring, but also to pass on their life experience to the younger generation.
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.