Answer: Sunken in pits.
- A On the upper surface only
- B Large and always open
- C Evenly spread out
- D Sunken in pits
Correct answer: D. Sunken in pits
Explanation: Xerophytes often have stomata sunk in pits, which traps humid air and reduces the rate of water loss.
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.