作业帮鱼在水中呼吸离不开氧气,那为什么在空气中不能生存?
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/03 04:38:19
鱼在水中呼吸离不开氧气,那为什么在空气中不能生存?
鱼在水中呼吸离不开氧气,那为什么在空气中不能生存?
鱼在水中呼吸离不开氧气,那为什么在空气中不能生存?
只能吸收水里溶解的氧气.
就像你只能吸收空气里的氧气一样.
鱼所要的氧是溶解在水中的氧
"The oxygen that fish breathe is not the oxygen in H2O. Instead, the fish are breathing O2 (oxygen gas) that is dissolved in the water. Many different gases dissolve in liquids, and we see an example ...
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"The oxygen that fish breathe is not the oxygen in H2O. Instead, the fish are breathing O2 (oxygen gas) that is dissolved in the water. Many different gases dissolve in liquids, and we see an example all the time in carbonated beverages. In these beverages, there is so much carbon dioxide gas dissolved in water that it rushes out in the form of bubbles.
Fish "breathe" the dissolved oxygen out of the water using their gills. It turns out that extracting the oxygen is not very easy -- air has something like 20 times more oxygen in it than the same volume of water. Plus water is a lot heavier and thicker than air, so it takes a lot more work to move it around. The main reason why gills work for fish is the fact that fish are cold-blooded, which reduces their oxygen demands. Warm-blooded animals like whales breath air like people do because it would be hard to extract enough oxygen using gills. "
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大意是:因为鱼的鳃只适应从水里吸收氧气，而对空气中的氧气不能吸收
收起
鱼用鳃从水里吸氧
其实鱼可以再空气中生存，不过要保持全身（特别是腮）湿润，因为鱼是通过腮中的一层层的血管来与水中的氧吸收得到氧气的，如果在空气中，血管会很快干燥无法吸收氧气，所以无法在空气中生存
氧气只是鱼生活的一个重要条件，并不能说有氧气鱼就能生存。
用鳃从水里吸氧