Here's why:
* Cell theory states that all living organisms are composed of cells. This means that every single living thing, from the smallest bacteria to the largest whale, is made up of one or more cells.
* Cells are the fundamental unit of life. This means that cells are the smallest units that can carry out all the processes necessary for life, such as metabolism, growth, reproduction, and response to stimuli.
* All cells arise from pre-existing cells. This means that new cells are always created by the division of existing cells.
Therefore, the structures that carry out the basic functions of living things are the individual cells that make up the organism.
