A comprehensive concept is a foundation builder. It is a short statement that combines the following four essential elements to form a strong base for your complex novel: (1) genre, (2) main character, (3) opposition, and (4) macro setting. You can arrange these elements, in any order.
The main respiratory surface in humans is the alveoli, which are small air sacs branching off from the bronchioles in the lungs. They are one cell thick and provide a moist and extremely large surface area for gas exchange to occur.t is a passive process (no energy is required) affected by factors such as the surface area available, the distance the gas molecules must diffuse across and the concentration gradient. Gases must first dissolve in a liquid in order to diffuse across a membrane, so all gas exchange systems require a moist environment.
Gas Exchange in the lungs. Exterior view of Alveoli. This is where gas exchange takes place in the lungs. Alveoli are tiny balloon-like sacs, in the lungs, where gas exchange takes place and they serve as the barrier between the external environment (the air) and the internal environment (the blood).