Plant Tissues

Guard cells

Guard cells are special kidney-shaped cells that surround the stomatal pore and control its opening and closing. These cells can change their shape to open or close the stomata, regulating gas exchange and water loss. Epidermal cells (option B) form the general outer layer but don't control stomata. Root hair cells (option C) are involved in water absorption, not stomatal control. Parenchyma cells (option D) are ground tissue cells for storage and support, not stomatal control.

Parenchyma, Collenchyma, Sclerenchyma

The three main types of ground tissue are Parenchyma (soft, thin-walled cells for storage), Collenchyma (thick-walled living cells for support), and Sclerenchyma (thick-walled dead cells for strength). Option B lists vascular tissues (xylem and phloem) and cambium (meristematic tissue). Option C lists components of dermal tissue. Option D lists types of meristematic tissues, not ground tissues.

Chlorenchyma

Chlorenchyma is a type of parenchyma that contains chloroplasts and performs photosynthesis. The chloroplasts in these cells capture light energy to make food for the plant. Aerenchyma (option B) contains air spaces for buoyancy in aquatic plants. Collenchyma (option C) provides structural support but doesn't contain chloroplasts. Sclerenchyma (option D) provides mechanical strength but cells are dead and cannot perform photosynthesis.

Transportation of water and food materials

Vascular tissue consists of xylem and phloem that are specialized for transportation. Xylem transports water and minerals from roots to other parts, while phloem transports food materials from leaves to all parts of the plant. Option B is the function of dermal tissue. Option C is the function of meristematic tissue. Option D is the function of ground tissue (storage parenchyma).