Chlorophyllous cells fewer in number, unique in shape with inner walls thicker are

Answer: Option A

Chlorophyllous cells are fewer in number, and unique in shape with inner walls thicker are Guard cells.
Guard cells are specialized plant cells in the epidermis of leaves, stems and other organs that are used to control gas exchange. They are produced in pairs with a gap between them that forms a stomatal pore.
Guard cells have low chlorophyll content and, low activity levels of RUBISCO and Calvin-Benson cycle enzymes.