A student compares gas exchange in two leaf samples. The samples were tested using the same method and under the same conditions.
The results are shown in the table.
| Leaf sample | Leaf thickness (mm) | Air spaces in spongy mesophyll (% of tissue volume) | Relative rate of gas exchange |
|---|---|---|---|
| P | 0.30 | 32 | 1.6 |
| Q | 0.55 | 18 | 0.8 |
Explain how the results support the conclusion that leaf sample P is better adapted for gas exchange.
80 exam-style questions on Edexcel GCSE Biology 6.2 Transport in plants, covering 6.2.1 Root hair cell adaptations, 6.2.2 Structure of xylem and phloem, 6.2.3 Transpiration and stomata, 6.2.4 Translocation of sucrose, 6.2.5 Leaf structure for photosynthesis, 6.2.6 Environmental factors on water uptake, 6.2.7 Rate calculations for transpiration, and 6.2.8 Plant adaptations to extreme environments. Each one has a worked solution and a mark scheme showing where the marks go.