Here's a breakdown:
* Cells: The basic building blocks of all living organisms.
* Tissue: A group of similar cells that work together to perform a specific function.
* Organ: A structure made up of different tissues that work together to perform a more complex function.
* Organ System: A group of organs that work together to carry out major bodily functions.
Examples of tissues:
* Epithelial tissue: Covers surfaces and lines cavities. Examples include skin, lining of the digestive tract.
* Connective tissue: Supports and binds other tissues. Examples include bone, cartilage, blood.
* Muscle tissue: Allows for movement. Examples include skeletal muscle, smooth muscle, cardiac muscle.
* Nervous tissue: Transmits signals throughout the body. Examples include brain, spinal cord, nerves.
