The diagram illustrates a model used to show the mass flow hypothesis of translocation. In a plant, what are the structures W, X, Y and Z, and in which direction does solution move along W?
- Aphloem: W; xylem: X; roots: Y; leaves: Z; direction of flow along W: from Z to Y
- Bphloem: W; xylem: X; roots: Z; leaves: Y; direction of flow along W: from Y to Z
- Cphloem: X; xylem: W; roots: Y; leaves: Z; direction of flow along W: from Y to Z
- Dphloem: X; xylem: W; roots: Z; leaves: Y; direction of flow along W: from Z to Y