Active Transport Requires Energy in Root Hairs

Steps:

• Identify that ion uptake in root hairs occurs against concentration gradients via active transport.
• Recall active transport needs ATP energy from cell respiration.
• Evaluate options: A relates to diffusion, C and D to osmosis, B to energy provision.
• Select B as it directly enables active transport of ions.

Why B is correct:

• Active transport uses ATP (energy from respiration) to move ions against gradients, as defined by the process requiring cellular energy input.

Why the others are wrong:

• A: Partially permeable walls allow passive diffusion, not active ion uptake.
• C: High vacuole ion concentration creates the gradient ions move against, not the uptake mechanism.
• D: Low water potential drives osmosis, irrelevant to ion active transport.

Final answer: B