Identifying root hair cell function in water absorption

Steps:

• Examine diagram for elongated shape with hair-like projection, typical of root cells.
• Recall root hair cells are in plant roots for uptake from soil.
• Link structure to function: large surface area aids absorption.
• Confirm primary role is water intake via osmosis, not transport or gas exchange.

Why D is correct:

• Root hair cells absorb water from soil through osmosis, driven by water potential gradient (higher in soil than cell).

Why the others are wrong:

• A: Xylem vessels transport ions upward in stems.
• B: Palisade mesophyll cells contain chloroplasts for photosynthesis.
• C: Guard cells around stomata regulate CO2 entry in leaves.

Final answer: D