Why the answer is B, and why the others tempt you.
**The reasoning**
Think of plants as having two transport systems, like two-way traffic. **Phloem** is the "food delivery system." After leaves make food through photosynthesis (combining CO₂, water, and sunlight to produce glucose), that sugar needs to reach every part of the plant — roots, stems, fruits, growing shoots. Phloem vessels carry these dissolved sugars and organic compounds from where they're made (usually leaves) to where they're needed or stored. This movement is called **translocation**.
**Why the wrong options tempt you**
- **A (Water)** — This is xylem's job! It's easy to mix them up, but remember: xylem = water UP, phloem = food around
- **C (Air)** — Plants exchange gases through stomata (tiny pores), not through vessels
- **D (Minerals only)** — Again, that's xylem bringing minerals dissolved in water from roots upward
**Quick takeaway**
**"Phloem = Food flow"** — both start with 'F'. Xylem carries water and minerals UP from roots; phloem distributes manufactured food (sugars) throughout the plant in all directions.
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