1. Proper food and drink.
2. Adequate sunlight and fresh air.
3. Getting rid of its waste matter constantly.
4. Protection from too much of cold or heat.
5. Daily exercise and rest.
6. Protection against disease-producing germs.
Each part of the body has its own use and is called organ. Several organs may work together, for examples, the mouth, teeth, gullet, stomach, small and large intestines and pancreas work together in the digestion of the food; which are collectively called the digestive organs. The nose, pharynx, trachea and lungs work together in getting fresh air into the body, and getting rid of the carbon dioxide; and for this reason they are called respiratory organs. The hearth and all the large and small blood-vessels work together in causing the blood to circulate through the body; and so they are called circulatory organs. The kidneys, skin, lungs, liver and large intestine work together in getting the waste matters out of the body; consequently, they called excretory organs. The brain, the spinal cord and all the large and small nerves work together in controlling all the organs of the body; these comprise the nervous system. In addition to the above-mentioned organs, there are bones, which serve as the framework and give shape to the body, while the muscles move all parts of the body.
Therefore, if all the parts of the body are protected and supplied with their needs one will have perfect healthy body.
