In the diagram of an epithelial cell, which letter most likely indicates the microvilli?

• A. A. The finger-like projections on the apical surface
• B. B. The dense region near the nucleus
• C. C. The area where two cells are tightly joined together
• D. D. The network of fibers in the cytoplasm

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the structure and function of microvilli. Microvilli are small, finger-like projections found on the apical surface of epithelial cells. Their primary function is to increase the surface area for absorption or secretion.
2. Step 2: Analyze the options provided in the question. Option A describes finger-like projections on the apical surface, which matches the description of microvilli. Option B refers to a dense region near the nucleus, which is likely the nucleolus or surrounding organelles. Option C mentions tight junctions, which are structures that join cells together. Option D refers to the cytoskeleton, which provides structural support within the cytoplasm.
3. Step 3: Relate the description of microvilli to the diagram. Microvilli are typically located on the apical surface of epithelial cells, which is the side facing the lumen or external environment. Look for finger-like projections in the diagram that match this description.
4. Step 4: Eliminate incorrect options based on their descriptions. Microvilli are not dense regions near the nucleus (Option B), tight junctions between cells (Option C), or cytoplasmic fibers (Option D). These structures serve different functions and are located in different areas of the cell.
5. Step 5: Confirm that Option A is the correct answer. The finger-like projections on the apical surface are characteristic of microvilli, which are specialized for increasing surface area and facilitating absorption or secretion.