Ion uptake depends on respiratory energy

Steps:

• Identify that respiration provides ATP energy for active transport of mineral ions into plant roots.
• Recall active transport requires energy, linking it directly to respiration.
• Evaluate observations: look for evidence showing reduced respiration impairs ion absorption.
• Select the choice demonstrating oxygen's role, as aerobic respiration needs oxygen.

Why D is correct:

• Respiration is aerobic, requiring oxygen to produce ATP; lower oxygen reduces respiration rate, decreasing energy for active ion uptake (per the process of cellular respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP).

Why the others are wrong:

• A: Root carbohydrate storage provides substrate for respiration but doesn't show energy dependence.
• B: CO2 from roots indicates respiration occurs but not its necessity for ion uptake.
• C: Large root hair surface aids diffusion but doesn't address energy requirement.

Final answer: D