Answer: Adhesion.
- A Cohesion
- B Tension
- C Adhesion
- D Diffusion
Correct answer: C. Adhesion
Explanation: Adhesion is water clinging to the xylem walls; cohesion is water sticking to itself - both help keep the water column intact.
Water can travel through cell walls (apoplast) or cell-to-cell through the cytoplasm (symplast) - but the Casparian strip at the endodermis blocks the apoplast route entirely, forcing everything through a selectively permeable membrane (symplast) before it can enter the xylem.
Concept context
Water and mineral absorption, the ascent of sap, transpiration, and phloem transport via the pressure flow hypothesis.