What are tissues primarily composed of?

Tissues are primarily composed of cells, which are the basic structural and functional units of life. In the context of biology, a tissue is formed when a group of similar cells come together to perform a specific function. For example, muscle tissue is made up of muscle cells that work together to facilitate movement, while nervous tissue is composed of nerve cells that transmit signals throughout the body.

Each type of tissue—such as epithelial, connective, muscle, and nervous tissue—plays a distinctive role in the body, underscoring the importance of cells in forming the foundation of these tissues. While organs are made up of multiple tissues, fluids and proteins can exist within tissues but do not define the composition of tissues themselves. Cells are the primary building blocks from which tissues are created, emphasizing their fundamental role in biology.