Human and animal tissues are groups of cells that work together to perform specific functions in the body. There are four main types of tissues: epithelial tissue, which covers surfaces; connective tissue, which supports and binds other tissues; muscle tissue, which enables movement; and nervous tissue, which transmits signals. Each type plays a crucial role in maintaining the overall health and function of an organism. These tissues are organized into organs, such as the heart or liver, which carry out complex tasks necessary for survival. Understanding tissues helps in fields like medicine and biology, as it provides insights into how bodies function and how diseases can affect them.