Answer: Cells
Explanation:
The cells are the smallest unit of the body of the living being. The number and size of the cell may vary depending upon the complexity in the function and life cycle of the living beings.
The cells are necessary for growth and reproduction in the organism. The growth process involves the increase in size and number of cells in an organism which facilitates it's increase in length.
The cells get split into daughter cells, by cell division hence, this way reproduce the progeny organisms.
