Adult tissues are specialized groups of cells that perform specific functions in the body. There are four main types of adult tissues: epithelial tissue, connective tissue, muscle tissue, and nervous tissue. Each type has unique characteristics and roles, such as protecting organs, supporting structures, enabling movement, and transmitting signals. These tissues work together to maintain the body's overall health and functionality. For example, muscle tissue allows for movement, while nervous tissue facilitates communication between different body parts. Understanding adult tissues is essential for studying anatomy and physiology, as they form the foundation of all organs and systems.