Vascular bundle structure in leaves

Steps:

• Recall that leaf vascular bundles in dicotyledons consist of xylem and phloem, with phloem positioned towards the upper epidermis and xylem towards the lower.
• Examine option B: it describes the bundle divided into two sections, phloem closer to upper epidermis, matching standard anatomy.
• Evaluate other options for inaccuracies in labeling, positioning, or features.
• Confirm B aligns with the accurate plan diagram by reflecting the correct orientation.

Why B is correct:

• In leaf vascular bundles, phloem is located adaxially (towards upper epidermis) for efficient sugar transport, as per plant anatomy definitions.

Why the others are wrong:

• A: Companion cells are part of phloem, but the option incorrectly implies they are separate from sieve tube elements in labeling.
• C: Companion cells are adjacent to sieve tube elements throughout the phloem, not specifically closer to the lower epidermis.
• D: Phloem sieve tube elements have thin, non-lignified walls for easy flow, unlike thick-walled xylem.

Final answer: B