Question

Stomata opens, because the guard cells have

• A. Thin outer walls
• B. Kidney shape
• C. Chlorophyll
• D. Large nuclei

Answer 1

The correct option is A Thin outer walls

The guard cells have outer thin walls and thick inner walls. During day time guard cells gain water and swell. When guard cells swell the inner wall cannot be pushed inside, because it is thick walled but outer wall can be pushed out, because it is thin walled. The thin outer wall when pushed outside actually pulls inner wall along radial micelles of cellulose fibrils. When inner wall is pulled out by outer wall, the stomata open.