Here's why:
* All living things are made of cells: Whether it's a single-celled bacterium or a complex human being, the fundamental building block of life is the cell.
* Cells carry out the functions of life: Cells are responsible for all the processes that keep an organism alive, including metabolism, reproduction, and response to stimuli.
* Cells are the smallest unit of life: While there are smaller structures within a cell, the cell itself is the smallest unit that can independently carry out the processes of life.
While there are variations in cell structure and function across different organisms, the cell remains the fundamental unit of life for all living things.
