The net force driving an uncharged molecule across the plasma membrane by passive transport is:
(a) concentration gradient
(b) charge of the molecule
(c) membrane potential
(d) more than one is correct

(a) Concentration gradient

Explanation:

The concentration gradient refers to the differences in the concentration of a substance across the plasma membrane. The passive transport of uncharged particles across the membrane is driven by differences in their concentration on either side of the membrane. The direction of the movement is down the concentration gradient.  

For example, passive transport of water across the membrane (osmosis) occurs from the region of its higher concentration to that of the lower concentration.  

answer:

the water molecules are transferred from the roots to the stem or top parts of the tall tree because of important properties of water which are adhesion, cohesion and capillary action. cohesion is the property of water molecules keeps water molecules in a combined state by sharing of bonds between them at the atomic level. adhesion allows the interaction of water molecules with other substances or substrate. adhesion will cause the attachment of water molecules to the wall of the vessel (xylem) of the plant. capillary action occurs when the adhesive force to the vessel wall is stronger than the cohesive force between water molecules. capillary action mimics the transfer of water from a tube or pipe. in this way water utilizes its property to transfer water from down to top level of the plant.  

what in the weirdo : o