The alveoli are lined with mucus and are surrounded by a network of blood capillaries. They have very thin walls for gases to be absorbed through. An individual air sac is called an alveolus. The layer of moisture in the alveoli allows gases to dissolve so that they can diffuse quickly.
Answer:
there is not enough oxygen for animal to turn to carbon.
Explanation:
D. sustainability increases i think
<span>The relationship between the number of organisms in the food chain and the size of the individual organisms within each level of the food chain is
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d) inversely proportional
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