Translocation moves solutes in plant phloem

Steps:

• Examine the diagram to identify region Z as phloem tissue in the stem cross-section.
• Recall phloem's role in transporting organic compounds like sugars from sources to sinks.
• Match the process to long-distance bulk flow of solutes under pressure gradients.
• Eliminate options not involving vascular tissue solute movement.

Why C is correct:

• Translocation is the active mass flow of sugars and nutrients through phloem sieve tubes, driven by source-to-sink pressure differences.

Why the others are wrong:

• A: Diffusion is passive and too slow for bulk transport over distances in stems.
• B: Osmosis involves water movement across membranes, not solute transport in phloem.
• D: Transpiration is evaporation pulling water through xylem, unrelated to phloem solutes.

Final answer: C