Answer: The respiratory system works with the circulatory system to provide this oxygen and to remove the waste products of metabolism. It also helps to regulate pH of the blood. Respiration is the sequence of events that results in the exchange of oxygen and carbon dioxide between the atmosphere and the body cells. The main purpose of respiration is to provide oxygen to the cells at a rate adequate to satisfy their metabolic needs. This involves transport of oxygen from the lung to the tissues by means of the circulation of blood. brainliest?