Tissue is a group of similar cells that work together to perform a specific function in the body. There are four main types of tissue: epithelial, connective, muscle, and nervous. Each type has unique roles, such as protecting organs, supporting structures, enabling movement, and transmitting signals. In plants, tissue also plays a crucial role. Plant tissues, like xylem and phloem, help transport water and nutrients throughout the plant. Understanding tissue is essential in fields like biology and medicine, as it helps us learn how living organisms function and how to treat various diseases.