The dissolved oxygen content in water
Answer:
The main sequence stretching from the upper left (hot, luminous stars) to the bottom right (cool, faint stars) dominates the HR diagram. It is here that stars spend about 90% of their lives burning hydrogen into helium in their cores. Main sequence stars have a Morgan-Keenan luminosity class labelled V.
Explanation:
Answer:
There is a higher oxygen content in the air of the lungs than that of oxygen-depleted blood and a lower carbon dioxide concentration. This gradient of concentration causes gas exchange during respiration.
Explanation:
I think it's A. Tell me if I'm wrong.
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