Xylem Vessel Features for Water Transport

Steps:

• Identify key xylem features: lignified walls for support, lack of end walls for continuous columns, and pits for lateral movement.
• Recall transport mechanism: cohesion-tension theory relies on these for efficient water flow without breakage.
• Match to options: all three features (1: lignified walls, 2: no end walls, 3: pits) contribute to vertical and lateral transport.
• Confirm A includes all essential roles.

Why A is correct:

• Lignified walls (1) provide rigidity against tension, no end walls (2) allow uninterrupted flow, and pits (3) enable water exchange per cohesion-tension theory.

Why the others are wrong:

• B omits pits, ignoring lateral transport.
• C omits no end walls, disrupting column continuity.
• D omits lignified walls, lacking structural support.

Not enough information on exact labels for 1,2,3, but assuming standard features, A fits.

Final answer: A