Question

State the three common features of all the respiratory organs like skin, gills, and lungs.

Answer 1

Respiration is the process of formation of energy for the purpose of completing the various metabolic reactions where the energy is produced and may sometimes be required to complete the process and result in the formation of certain end products.

Complete answer
Respiration is the process of inhaling oxygen and exhaling carbon dioxide, it takes place through various organs depending upon the animals and their habitat. Respiration is an oxidation process that involves the degradation of a complex organic compound, this carbon dioxide, water, and energy are produced.
The three common features of all the respiratory organs like skin, gills, and lungs are as follows:

1. All these organs constitute very thin walls that will help them to exchange and diffuse respiratory gases and other substances easily.
2. They all are able to absorb a large amount of oxygen due to the presence of huge surface areas.
3. The respiratory gases are easily transported through these organs as they constitute several blood vessels thus resulting in a large blood supply.

Additional information
Every individual needs the energy to perform various processes of the body. This energy is produced through respiration. The molecules of carbohydrates that are stored in the body will break down into simpler molecules during the process of respiration and help in the production of energy. Respiration is of two types based on the presence or absence of oxygen, aerobic respiration (oxygen present), and anaerobic respiration (oxygen absent).
During respiration in living organisms, the oxygen is inhaled while the carbon dioxide is exhaled through the lungs mostly, this process is termed breathing. There are three respiratory surfaces present on the body of the frog which are used during the process of exchanging gas with the environment; they are; the skin, the lungs, and the lining of the mouth.

Note:
The process of respiration is not the same in various organisms. In unicellular animals, the exchange of gases takes place through the cell surface such as amoeba. In man, it takes place through the lungs. Earthworms use their skin for the exchange of gases. In insects like cockroaches, transportation of gas takes place in tracheae. The respiration in aquatic animals mostly occurs through gills.