Q. The tissue is a group of cells that
(a) Have a common origin.
(b) Are always structurally similar.
(c) Perform a common function.

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Solution:

The tissue is a level of cellular organization. Cells make a group to form a tissue which has a common origin and usually performs a common function. Each tissue specialized to perform a unique function, and they can be combined with other tissue to form organs such as leaves, roots, flowers, etc. Though the cells of many plant tissues are structurally similar (e.g. parenchyma), but the cells of a particular tissue may not be structurally similar (e.g. xylem). In plants, tissues are of two types-
  • Meristematic tissue and
  • Permanent tissue.
Meristematic tissue consists of those type of cells which can divide. These cells are undifferentiated and immature. Meristematic cells have prominent nuclei and dense cytoplasm. Vacuoles are absent in these cells and intercellular space is also absent. They are present at a specific location in the plant. Meristematic cells differentiate and specialized to form permanent cells. Permanent cells lose the power of division and placed at a fixed position in plants. These cells can be dead or living, and they have permanent shape, size, and function.