Types discussion: Autism (a developmental brain disorder characterized by impaired social interaction and communication skills, and limited range of activities and interests) is the most characteristic and best studied PDD.
A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing.hese secondary meristems are also known as lateral meristems because they are involved in lateral growth. At the meristem summit, there is a small group of slowly dividing cells, which is commonly called the central zone.
A meristem is the tissue in most plants containing undifferentiated cells, found in zones of the plant where growth can take place. Meristematic cells give rise to various organs of the plant and keep the plant growing. There are three types of meristematic tissues: apical, intercalary and lateral. There are two types of apical meristem tissue: shoot apical meristem, which gives rise to organs like the leaves and flowers, and root apical meristem, which provides the meristematic cells for future