Describe the structures involved in gas exchange in the human respiratory system and compare it to other organisms.

a) P: Trachea Q: Ribs b) The function of part R (intercostal muscles) is to contract and relax to move the rib cage during breathing, facilitating inhalation and exhalation. c) Part S (alveoli) is adapted to its function of gas exchange by having: • A large total surface area for efficient diffusion of gases. • Thin walls (one cell thick) to reduce the diffusion distance. • A rich blood supply (capillary network) to maintain a steep concentration gradient for gases. • A moist surface to dissolve gases, allowing for easier diffusion. d) The structure that performs the same function (gas exchange) as the illustrated system in: i) Amoeba: Cell membrane ii) Fish: Gills That's 2 down. 3 left today — send the next one.