Standard tissues in dicot leaf cross-section

Steps:

• Recall dicot leaf structure: upper/lower epidermis, palisade mesophyll, spongy mesophyll, vascular bundles (xylem, phloem).
• Identify required labels: must include epidermal layers, mesophyll types, and vascular elements.
• Evaluate options for accuracy against leaf anatomy diagram.
• Confirm option with all valid, present tissues.

Why A is correct:

• Lower epidermis covers underside; phloem transports sugars in veins; spongy mesophyll allows gas exchange; palisade mesophyll maximizes photosynthesis—all standard in dicot leaf sections.

Why the others are wrong:

• B: "Upper" is incomplete (should specify epidermis); no lower epidermis or palisade.
• C: Endodermis is root-specific, not in leaves.
• D: Companion cells are phloem-associated but not a primary label; waxy cuticle is present but xylem and spongy mismatch typical sets.

Final answer: A