The region of meristematic activity is the place where thin-walled cells with dense protoplasm divide repeatedly.

• A. Region of Meristematic Activity
• B. Region of Elongation
• C. Region of Maturation
• D. Region of Differentiation

Answer: (A)

Active cell division happens in the region of meristematic activity. In this zone, cells are small, with thin cell walls and dense cytoplasm, and they divide rapidly to produce new cells. That combination of being compact and highly mitotic is exactly what you’d expect in a region dedicated to growth by division, so this region is the best match for the description.

Along the root and shoot tips, the progression is clear: behind the root cap or at the growing tips, the meristematic region generates new cells; just above it, cells begin to elongate and lengthen as they take up water; further up, cells differentiate and mature into specialized tissues. In the region of elongation, cells expand rather than divide, so they’re not characterized by dense protoplasm and repeated division. In maturation or differentiation regions, cells stop dividing and acquire specialized structures and thickened walls, not the thin-walled, highly mitotic state seen in meristematic tissue.

So the described cells—thin-walled and densely packed with protoplasm that divide repeatedly—fit the region where active cell division occurs, making it the correct choice.