Final answer:
Laminar flow typically occurs in large airways due to lower air velocity which allows smooth, streamline movement of air. Turbulent flow, however, is commonly found in small airways where high air velocity or obstructions create irregular flow paths, mixing, and increased resistance. Option b is correct.
Step-by-step explanation:
Laminar flow occurs in large airways, whereas turbulent flow occurs in small airways. This is because in large airways, the air velocity is generally lower, and the layers of air can flow smoothly without mixing, characterized by parallel, regular paths referred to as streamlines.
On the other hand, in small airways, especially where there are obstructions or high air velocity, turbulent flow occurs leading to the mixing of the air layers and the creation of swirls and eddies. This turbulent behavior can increase resistance, generate more heat, and cause more interaction between the air and the airway surfaces.
Figures illustrating these concepts often show laminar flow as smooth and continuous, while turbulence appears to disrupt and mix the path of the flow. Turbulent flow is typically caused by obstruction, high speeds, or sharp corners which impart velocities perpendicular to the main direction of flow. Therefore, the correct answer to the student's question is: b) Small, large.