Cell theory states that cells are the basic morphological and functional units for the maintenance of life, that is, all living beings must be formed by cells, so it is impossible for a living being without at least one cell in its constitution. . This concept explains our body's need to replace the cells that we lost for some reason.
In that case, we can say that cell theory states that cells are the basic unit of life and this supports the idea that a new cell will replace damaged cells in a scratched knee.