Tissues – Class IX
The human body and plants are made up of billions of cells. A single cell cannot perform all life activities efficiently, so groups of similar cells join together to perform specific functions. Such a group of cells is called a tissue . 1. Definition of Tissue A tissue is a group of structurally and functionally similar cells that work together to perform a particular function. In unicellular organisms (e.g., Amoeba), one cell performs all activities. In multicellular organisms , division of labour exists through specialised tissues. 2. Types of Tissues (A) Plant Tissues Plant tissues are broadly classified into Meristematic and Permanent tissues . (i) Meristematic Tissue Made up of actively dividing cells. Thin cell wall, dense cytoplasm, large nucleus, no vacuoles. Types: Apical meristem: At root and shoot tips; helps in growth in length. Intercalary meristem: At internodes, it helps in the growth of organs. Lateral meristem (cambium): Hel...