We live in an amazing world with so many creatures like us. The greatest of all the creations on earth is the man himself, the marvelous machine, very precise and efficient in nature. The human body has a dynamic framework of bones and cartilages called the skeleton. The human skeleton is way too flexible, with the hinges and joints that were made by the creator for us to move. Also in order to cut down the harmful frictions, such moving parts must get lubricated. Just like the man-made machines are lubricated by an outside source.