Plasmodesmata in Phloem vs. Xylem Cells

Steps:

• Plasmodesmata are channels linking cytoplasm of adjacent living plant cells for transport and signaling.
• Phloem sieve elements connect to companion cells via plasmodesmata to support sucrose loading.
• Companion cells maintain these connections as living support cells for sieve elements.
• Xylem vessel elements mature into dead, hollow conduits without cytoplasm or plasmodesmata.

Why B is correct:

• B (✓ ✓ X) matches the presence of plasmodesmata in living phloem cells and absence in dead xylem vessels, per plant cell biology definitions.

Why the others are wrong:

• A: Falsely shows xylem vessel with plasmodesmata, ignoring its dead state.
• C: Incorrectly denies plasmodesmata in both phloem cells, contradicting their living connections.
• D: Same error as C, misrepresenting phloem function.

Final answer: B