Levels of Organisation

• • Atom: The smallest unit of matter that can't be broken down without releasing energy 
• • Organelle: any of a number of organized or specialized structures within a living cell. A structure within a cell that helps it function.
• • Cell: The basic unit of life : A cell is a single-celled organism that can reproduce and grow.
• • Tissues: A higher level of organization than cells, tissues are made up of a specific type of cell. For example, muscle tissue is made up of muscle cells. 
• Organs: Made up of tissues, organs are part of the next level of organization.
• • Organ systems: A higher level of organization than organs, organ systems are made up of functionally related organs. 
• • Organism: The highest level of organization, an organism is a living being that can perform all the functions necessary for life.