Question

What advantage over an aquatic organism does a terrestrial organism
have with regard to obtaining oxygen for respiration?​

Answer 1

Aquatic animal, such as fishes , obtain oxygen for respiration which is dissolved in water . The amount of oxygen dissolved in water is very low . On the other hands , the terrestrial organisms take oxygen directly from the air .

Answer 2

Terrestrial organisms take up oxygen from the atmosphere whereas aquatic animals obtain oxygen from water. Air contains more O2 as compared to water. Since the content of O2 in air is high, the terrestrial animals do not have to breathe faster to get more oxygen.