1. Cells: The basic unit of life. They are the smallest unit that can carry out all the functions necessary for life.
2. Tissues: Groups of similar cells that work together to perform a specific function. Examples include muscle tissue, nervous tissue, and epithelial tissue.
3. Organs: Structures made up of two or more different tissues that work together to perform a specific function. Examples include the heart, lungs, and stomach.
4. Organ Systems: Groups of organs that work together to perform a major bodily function. Examples include the digestive system, respiratory system, and circulatory system.
5. Organism: A complete living thing made up of multiple organ systems that work together to sustain life.
This hierarchy of organization allows multicellular organisms to be far more complex and efficient than single-celled organisms. Each level builds upon the previous one, creating increasingly complex and specialized structures that enable the organism to perform a wider range of functions.
