I would say the alveoli. They are tiny air pockets in the lungs: this is where the diffusion of oxygen and carbon dioxide occurs.
Hope this helps! x
<span>Both the populations of Drosophila seem to have the same gene for foraging behavior
Therefore, the </span><span>alternative hypothesis which is made far less likely by having three R and K lines, rather than one of each is:
</span><span>The difference between the R and K lines is the result of environmental differences in the food availability of their habitats.
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D. One that is the large in diameter and has high blood volume
Individual , population , community then ecosystem.