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.
Importance of air. 1. Essential supplier of energy: All living beings including plants & animals are dependent on air oxygen for generation of valuable life energy. Body cells take up oxygen from blood and generate energy from food in the form of ATP. This biochemical generation of ATP is a basic requirement to sustain life on earth.