Question

What keeps the force of gravity from overcoming transpirational pull?

A. upward pressure from the roots
B. high water pressure in the leaves
C. movement of water toward a sugar sink
D. cohesion and adhesion of water molecules
E. the Casparian strip blocking water molecules from moving out

Answer 1

Cohesion and adhesion of water molecules enable transpiration pull to overcome the force of gravity, allowing water to move upward from the roots to the leaves in plants.

Step-by-step explanation:

The force of gravity does not overcome transpirational pull in plants thanks to the cohesion and adhesion of water molecules. Cohesion refers to the attraction between water molecules themselves, which creates a chain-like effect as water moves upwards through the plant's xylem vessels. Adhesion is the attraction between water molecules and the walls of the xylem vessels, allowing for capillary action. This effect, combined with the negative pressure generated by water evaporating from the leaves during transpiration, is responsible for pulling water from the roots to the leaves against the force of gravity.