▶️ Answer/Explanation
The correct sequence follows the transpiration stream in plants. Water first enters through root hair cells via osmosis. It then moves through the root cortex cells (via the apoplast or symplast pathways). Next, it enters the xylem vessels in the root’s stele, which transport it upwards to the leaves. Finally, water exits the xylem and moves into the mesophyll cells in the leaf, where it evaporates during transpiration. Therefore, the correct order is: root hair cells → root cortex cells → xylem → mesophyll cells.
✅ Answer: (D)
✅ Answer: (D)
▶️ Answer/Explanation
Water enters the plant via root hair cells through osmosis due to a water potential gradient. It then moves through the root cortex cells via the apoplastic or symplastic pathways until it reaches the xylem. The xylem acts as a structural “pipeline,” transporting the water upwards to the leaves through transpiration pull. Finally, the water exits the xylem and enters the mesophyll cells of the leaf, where it is used for photosynthesis or evaporated into the air spaces for transpiration. This sequential flow from soil to leaf makes choice D the only logically sound biological path.
✅ Answer: (D)
✅ Answer: (D)
▶️ Answer/Explanation
Detailed solution
The correct answer is C.
Reasoning:
Xylem is a specialized vascular tissue responsible for the upward transport of water and dissolved mineral ions from the roots to the rest of the plant. In contrast, the phloem transports organic nutrients like sucrose and amino acids (Options A and D). Carbon dioxide (Option B) is primarily exchanged through stomata via diffusion. Therefore, only the transport of mineral ions describes a primary function of the xylem vessels in the stem.