The oxygen is relatively insoluble in plasma. At normal atmospheric pressure, only 0,3% of oxygen dissolves. That why there are respiratory pigments that <u>elevate almost 70 times</u><u> the capacity to transport O₂ of blood</u>. The most common respiratory pigments are hemoglobin (in all vertebrates and some invertebrates) and hemocyanin (in mollusks and arthropods).
B. Healthier ecosystems. If you're talking about benefits, this is the only positive on this list. The others are listing the difficulties or downsides.
