Which of the following cells is a specialized cell?

Step 1: Analyze the question The question asks which cell is specialized, meaning a cell that has developed a particular structure to carry out a particular function.

Step 2: Concept Cell specialization (differentiation) happens when a cell takes on a particular shape and structure that suits a specific job. Examples include:

• Red blood cells (carry oxygen)
• Root hair cells (absorb water)
• Palisade cells (photosynthesis)
• Guard cells (control opening and closing of stomata)

Step 3: Examine each option

• A. Amoeba: A single-celled organism. It carries out all life functions itself, so it is a whole organism, not a specialized cell in a multicellular body.
• B. Plasmodium: Also a unicellular parasite, which is likewise an organism and not a specialized cell.
• C. Guard cell: A bean-shaped cell found in pairs around the stomata of leaves. It has thick inner walls and chloroplasts, and it changes shape to open or close the stoma, which regulates gas exchange and water loss. This is a clear specialization of structure to function.
• D. Meristematic cell: An unspecialized (undifferentiated) cell that divides actively at the root and shoot tips. It has not yet taken on a specific function.

Step 4: Answer The guard cell is the specialized cell.

Tip: Meristematic cells are like "undecided students" because they can still become anything. Once a cell has a specific job and a matching structure (guard cell, root hair cell, red blood cell), it is specialized.