Question

According to capillarity theory ______ alone causes ascent of sap in plants.

Options

• Hydrostatic pressure

• Osmotic pressure

• Transpiration pull

• Physical forces and dead cells

Answer 1

According to capillarity theory physical forces and dead cells alone causes ascent of sap in plants.

Explanation:

According to the capillarity theory, the ascent of sap is caused by physical forces (surface tension, cohesion, adhesion) acting through the dead xylem vessels, which act like narrow capillary tubes. This theory does not involve osmotic pressure, hydrostatic pressure, or transpiration pull, those belong to other theories of water ascent.