Tissue is an organizational level between cells and organs. There are four basic types of animal tissue: connective, muscle, nervous, and epithelial. Connective tissue holds organs together and has fibers. Muscle tissue produces movement. Nervous tissue forms the brain and nerves. Epithelial tissue forms protective barriers around organs. Plant tissues include vascular, ground, and epidermal tissues which transport fluids, store nutrients, and form surfaces. Meristematic tissues enable plant growth. Tissues differentiate into permanent simple tissues like parenchyma and complex tissues like xylem and phloem which transport water and nutrients.