A tissue is a group of cells that are similar in structure and work together to perform a specific function. Tissues are present in multicellular organisms and provide structural strength, mechanical strength, and show division of labor. There are four main types of animal tissues: epithelial, connective, muscular, and nervous tissue. Plant tissues are broadly categorized into three tissue systems: dermal, ground, and vascular tissue. The classification of plant tissues is mainly based on the different parts of plants and the different types of cells.