The correct option is D Part 2 - Cortical cells, Part 4 - Xylem
∙ This is a diagrammatic representation of a part of the cross section of the root in the root hair zone showing cell to cell conduction of water to xylem. Various parts of the diagram include:
1) Root hairs are represented by part 1.
2) Soil particles are represented by part 2.
3) Xylem is represented by part 3.
4) Cortex/cortical cells are represented by part 4.
∙ The passage of water is from the soil to the root hair. It is as a result of endosmosis. The solution outside the cell has a lower solute concentration than the fluids inside the cell. So, the water molecules from outside will move into the cell.
∙ Root pressure is responsible for the movement of water in the direction indicated by the arrows in the diagram. Root pressure is the pressure set up due to the alternate turgidity and flaccidity of root hair cells and cortical cells, pushing water from soil to xylem of root and upwards of xylem to a certain height.