Question

what advantage of the aquatic organism have with regard to obtaining oxygen for respiration

Answer 1

Aquatic organisms take up the oxygen present in the water through their gills. As the amount of oxygen in air is more than the oxygen present in water, we, the terrestrial organisms don't have to breathe faster but the aquatic organisms have to.

Answer 2

the aquatic organisms use the oxygen dissolved in water for carrying out respiration. The amount of oxygen dissolved in water however, limited. The terrestrial organisms take oxygen from air which contain much higher amount of oxygen. Thus, a terrestrial organism have an advantage over an aquetic organism in regard to obtain oxygen because it is surrounded by an oxygen-rich air from which it can take any amount of oxygen.

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