The unity of the organic world is evidenced by cellular theory. Its essence can be expressed in two main provisions: 1) the cell is an elementary structural unit of plants and animals; 2) the cells of plants and animals are homologous in their development, but similar in function.
Currently, the basic principles of cellular theory are formulated as follows: 1) a cell is a universal structural unit of living matter; 2) each cell originates only from another cell; 3) the cells of all organisms have a similar structure and composition; 4) cells of multicellular organisms are interconnected, forming an integrated system.
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.