2.35 describe the role of stomata in gas exchange

2.35 •stomata: •let carbon dioxide and oxygen diffuse in and out and let water leave

                         (transpiration)

                        •they close when it gets dark, since photosynthesise can’t happen, so no need for carbon dioxide 

                                  •water can’t escape when they are closed, stopping dehydration in the plant

                                            •they also close when the roots dry up, preventing photosynthesis, but saving it from death 

                                            •they are controlled by the guard cells (next to the stomata)