1. Cells: The basic building blocks of life, consisting of a cell membrane, cytoplasm, and various organelles.
2. Tissues: Groups of similar cells that perform a specific function, such as muscle tissue or connective tissue.
3. Organs: Structures made up of different tissues that perform specific tasks, such as the heart, lungs, and liver.
4. Organ systems: Groups of organs that work together to perform a larger function, such as the digestive system or the respiratory system.
5. Organisms: Complete living things, such as plants, animals, and fungi.
6. Populations: Groups of organisms that live in the same area and interact with each other, such as a flock of birds or a pride of lions.
7. Communities: Groups of populations that interact with each other in the same ecosystem, such as a forest community or a grassland community.
8. Ecosystems: The interactions between living organisms and their physical environment, including the climate, soil, water, and other living things.