- A Tight junctions sealing the membranes of adjacent cells together
- B Plasmodesmata (for loading and unloading sugars)
- C Lignified cell walls with no cytoplasmic continuity between cells
- D Gap junctions formed from connexin protein channels as in animal cells
Correct answer: B. Plasmodesmata (for loading and unloading sugars)
Explanation: Companion cells are metabolically active and support sieve tube elements via extensive plasmodesmata connections. They load and unload sugars.
Concept context
Water and mineral absorption, the ascent of sap, transpiration, and phloem transport via the pressure flow hypothesis.