Answer: Phosphorus and water.
- A Only carbon dioxide
- B Only oxygen gas
- C Phosphorus and water
- D Only sunlight energy
Correct answer: C. Phosphorus and water
Explanation: The fungal hyphae of a mycorrhiza greatly extend the absorbing surface, mainly boosting uptake of phosphorus and water.
Water can travel through cell walls (apoplast) or cell-to-cell through the cytoplasm (symplast) - but the Casparian strip at the endodermis blocks the apoplast route entirely, forcing everything through a selectively permeable membrane (symplast) before it can enter the xylem.
Concept context
Water and mineral absorption, the ascent of sap, transpiration, and phloem transport via the pressure flow hypothesis.