ફેફસા શ્વાસ દરમિયાન ક્યારેય દબાઈ જતાં નથી અને થોડી હવા ફેફસામાં રહે છે. તે ક્યારેય કાઢી શકાતી નથી, કારણ કે \(........\)

(b) : Intrapleural pressure is the pressure of air within the pleural cavity. Intrapleural pressure is always negative, which acts like a suction to keep the lungs inflated and prevent them from collapsing. The negative intrapleural pressure is due to three main factors: surface tension of the alveolar fluid; elasticity of lungs; elasticity of thoracic wall. Normally, there is a difference between intrapleural and intrapulmonary pressure, which is called transpulmonary pressure. This transpulmonary pressure creates the suction to keep the lungs inflated. If there is no pressure difference, there is no suction and lungs will collapse.