Here's why:
* Basic Building Block: Cells are the fundamental building blocks of all living organisms, from single-celled bacteria to complex multicellular animals.
* Self-Contained Units: Each cell is a self-contained unit capable of carrying out the basic processes of life, such as metabolism, growth, and reproduction.
* Specialized Functions: While all cells share some basic functions, different types of cells within an organism are specialized for specific tasks. For example, muscle cells contract to enable movement, nerve cells transmit signals, and red blood cells transport oxygen.
While smaller structures like organelles exist within cells and perform specific functions, they are not considered independent units of life in the same way that cells are.
