During a night, a plant has 2 m² of roots and absorbs 0.6 m³ of air per hour from the soil. What volume of oxygen is available for respiration? (Assume air contains 21 % oxygen).

Step-by-step solution

1. Determine the volume of oxygen in the absorbed air by multiplying total air volume by the percentage of O₂.
2. $0.6{\text{ m}}^3\times 0.21=0.126{\text{ m}}^3$
3. Convert cubic metres to litres: $1{\text{ m}}^3=1000\text{ L}$.
4. $0.126{\text{ m}}^3\times 1000=126\text{ L}$

Concept tested: Oxygen availability in root respiration

Published 7 October 2026 · How this solution was prepared and checked