The correct answer is option 4: Respiration. The lungs are the primary organs of the respiratory system, which is responsible for the process of respiration. Respiration is the exchange of oxygen and carbon dioxide between an organism and its environment.
Option 1: Digestion is incorrect because the lungs are not involved in the process of digestion, which takes place in the gastrointestinal system.
Option 2: Constipation is incorrect because the lungs do not have any role in the process of constipation, which is related to the digestive system and the intestines.
Option 3: Perspiration is incorrect because the lungs do not play a role in the process of perspiration, which is controlled by the sweat glands and is part of the body`s temperature regulation mechanism.