AP BIOLOGY

Detailed explanation-1: -Capillary action helps bring water up into the roots. But capillary action can only “pull” water up a small distance, after which it cannot overcome gravity. To get water up to all the branches and leaves, the forces of adhesion and cohesion go to work in the plant’s xylem to move water to the furthest leaf.

Detailed explanation-2: -As water molecules evaporate from plant leaves, they attract the water molecules still in the plant, helping to pull water up through the stems from the roots. The combination of transpira-tion and capillary action delivers the water from the bottom to the top of a plant.

Detailed explanation-3: -Water moves into the roots from the soil by osmosis, due to the low solute potential in the roots (lower s in roots than in soil). This intake o f water in the roots increases p in the root xylem, driving water up.

Detailed explanation-4: -Because water molecules like to stick together (cohesion) and like to stick to the walls of the tubes of cellulose (adhesion), they rise up the tubes all the way from the roots to the leaves. Water then evaporates from the leaves, helping to draw up more water from the roots. This process is called capillary action.

Detailed explanation-5: -Xylem transports water in plants. Water is absorbed from the soil through root hair cells. Water moves by osmosis from root cell to root cell until it reaches the xylem. It is transported through the xylem vessels up the stem to the leaves.