a.Why is it important that the trachea is reinforced with cartilage rings? Of what advantage is it that the rings are incomplete posteriorly? b.Differentiate between atmospheric pressure, intrapulmonary pressure, and intrapleural pressure. Which of these is always negative in a healthy individual? What happens if intrapleural pressure becomes equal to atmospheric pressure? c.While having a physical examination, a young male informed his doctor that at age 8 he had lobar pneumonia and pleurisy in his left lung. The physician decided to measure his VC. Describe the apparatus and method used for taking this measurement. Define the following terms used in the description of lung volumes: TV, IRV, ERV, RV, and VC. d.After a long scuba diving session on a Caribbean reef, Carl boards a plane to Dallas. He begins to feel pain in his elbow on the flight back to Dallas. What is happening to him and why? How does he need to be treated?