Cold sores - painful sores on the lips and around the mouth, caused by a virus. Canker sores - painful sores in the mouth, caused by bacteria or viruses. Thrush - a yeast infection that causes white patches in your mouth. Leukoplakia - white patches of excess cell growth on the cheeks, gums or tongue, common in smokers.
Energy and Metabolism. All living organisms need energy to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is the set of life-sustaining chemical processes that enables organisms transform the chemical energy stored in molecules into energy that can be used for cellular processes.
Anyway, the likely reason that green is important is that plant life was a very large part of what we needed to look at for a very long time, and the same for the ancestors of humanity. If you live in a suburb it might be hard to notice, but the natural world is almost entirely green when viewed from a distance.