Identifying xylem in a plant stem cross-section

Steps:

• Recall that xylem transports water and minerals upward from roots.
• Examine the diagram for vascular bundles in a dicot stem, where xylem faces the pith (center).
• Note positions: A and B are outer phloem, C is cambium, D is inner xylem.
• Confirm D's location matches xylem's structural role in support and conduction.

Why D is correct:

• Xylem consists of lignified vessels and tracheids for water transport, positioned inward in stems per vascular tissue organization.

Why the others are wrong:

• A labels phloem, which transports sugars downward.
• B labels epidermis or cortex, protective outer layers.
• C labels cambium, meristematic tissue for growth.

Final answer: D