Question

What advantage over an aquatic organism does a terrestrial organism have with the regard to obtaining oxygen for the respiration?
a. Air contains about 21% of oxygen while water has 1% oxygen in dissolved state.
b. A terrestrial organism is able to get several more times oxygen than an aquatic animal.
c. Both A and B.
d. None of the above.

Answer 1

Hint: The rate of breathing is more in fishes as compared to elephants. About 80% of oxygen is produced by the phytoplankton. In eukaryotic cells, cellular respiration occurs in mitochondria.

Complete answer:
Respiration is the process in a living organism in which an organism intakes oxygen from the atmosphere and releases the carbon dioxide, produced by the oxidation of mainly carbohydrates. In this process, energy is also produced.

The aquatic animals are the animals which live in water, which may be marine, fresh and brackish water. For example- fishes, sponges, Hydra etc.
In water, oxygen is present in the dissolved form.
The percentage of oxygen is very low, it is about ten molecules of oxygen per million of water.
The oxygen can be added in the water in two ways-
(a) It can be produced as a by-product of photosynthesis done by the aquatic plants.
(b) It can be added on the surface of water due to the action of winds.
As the percentage of oxygen is very low in the water, aquatic organisms have to show a much faster rate of breathing as compared to terrestrial organisms to get a sufficient amount of oxygen.

The terrestrial animals are the animals which live on the land. For example- humans, cats, dogs, elephants, lions, giraffes etc.
In the atmosphere, air contains about 21% of oxygen.
The terrestrial organisms utilize this oxygen with the help of respiratory organs. So, they breathe at a lesser rate as compared to the aquatic animals.

Hence, The correct answer is option (C).
Because air contains about 21% of oxygen while water has 1% oxygen in dissolved state and A terrestrial organism is able to get several times more oxygen than an aquatic animal.

Note: In water, oxygen can be added by the aerating action of wind. The utilization of energy is high in aquatic animals compared to terrestrial animals because aquatic animals show more breathing rate as compared to that of terrestrial animals to get a sufficient amount of oxygen.