Identifying xylem in a plant stem cross-section

Steps:

• Recall that xylem transports water and minerals upward, featuring lignified, thick-walled vessels and tracheids.
• In a stem cross-section, xylem forms the inner vascular bundle region, often appearing darker or woody.
• Compare labelled parts to xylem's distinct tubular, non-living cells versus softer surrounding tissues.
• Select the part matching xylem's central, supportive structure.

Why C is correct:

• Part C exhibits thick-walled, hollow vessels typical of xylem, as defined by its role in providing structural support and water conduction via dead, lignified cells.

Why the others are wrong:

• A: Represents epidermis, the thin outer protective layer without lignified elements.
• B: Indicates phloem, containing sieve tubes for downward sugar transport, lacking xylem's rigidity.
• D: Shows cortex, composed of thin-walled parenchyma for storage, not transport.

Final answer: C