Why are the cells of the alveoli so flattened?

Gas exchange occurs in the alveoli of the lungs and each is made from a single layer of flat cells, Many alveoli in the lungs, so a large surface area for exchangement of C02 and O2. They are surrounded by a network of capillaries and oxygen diffuses out of them via the alveolar epithelium to the hemoglobin.

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c: warm water flows from the western tropical pacific toward south america. that should be the right answer! hope it .

rising temperatures because when water vapor in the air is cooled, it condenses. it turns back into a liquid and attaches to dust particles in the air. these very small water droplets group together to form clouds