In unicellular organisms, the cell performs the functions of the whole organism, while in multicellular organisms they perform certain functions, differentiate in structure and function.
The cells of multicellular organisms perform one or more specific functions. In this case, their structure is greatly simplified, but the specific function is performed by the cell much more efficiently.
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.