Science Photo Answer #844
Just before I left for my journey, I got a new microscope for doing microphotography and microvideo. I have not had a lot of time to play with it, but I managed to take this photo of something from our refrigerator. What is it?
This is a photo of the underside of a celery leaf. The dark structures in the photo are the guard cells for stoma, openings in the leaf that let carbon dioxide into the leaf and let water vapor out. By opening and closing the stoma, the plant can control how much water escapes from the leaf, which also controls the movement of water and nutrients up from the plants roots. You can find out more about that in the Heartless Plants video.