Yet there are people who poison their own lungs with smoke of tobacco and other substances. Second only to air in importance is water. Air is easily accessible to humans, because it covers the entire surface of the earth. Drinkable water can be found in abundant qualities in almost all parts of the earth. Water is the essential solution for most of the chemical processes that transpire in the body.
Excess water is released periodically through urination and perspiration.
Finding sufficient water and food means that humans need to work in some way to obtain these necessary nutrients. Our foods consist of carbohydrates, proteins, fats, vitamins, and minerals which the cells of our body break down into amino acids, fatty acids, and glucose in order to manufacture the substances needed for the energy processes of the body. The result is that the body is capable of doing work that not only can provide the necessities of life but also for doing many other things as well. Many diverse foods can be used to obtain a balanced diet of nutrients for the body. For example, it is not necessary to eat meat to obtain all the required proteins for optimal health.