Question

Explain the role of cohesive force in the ascent of sap.

Answer 1

• Cohesive force is the strong mutual attraction between molecules of the same substance, specifically between water molecules.
• Inside the narrow tubes of the xylem, this force holds the water molecules tightly together, creating a continuous, unbroken water column.
• When transpiration pull tugs water out from the top of the leaves, this cohesive column prevents the water chain from breaking, allowing the upward movement (ascent of sap) to happen smoothly over great heights.