Tissue is a group of cells performing a particular function.
Tissues are mainly of two types.
(i) Meristematic tissues: These tissues contain immature and young cells that are much active and capable of showing continuous divisions and redivisions. They may be promeristem, primary meristem, secondary meristem, apical meristem, intercalary meristem and lateral meristem.
(ii) Permanent tissues : These are made up of mature cells which have lost the capacity to divide and have attained a permanent shape, size and function e.g., Simple (Parenchyma, collenchyma, sclerenchyma), complex (xylem, phloem) and secretory tissue.