The organic substances, which are catabolised in the living cells to release energy are called as respiratory substrates. Though carbohydrate, fat or protein may act as a respiratory substrate, but the common respiratory substrate is glucose.

Glycolysis takes place in the cytoplasm of cell and does not need oxygen. Its is a common process in all living beings. Glycolysis was discovered by three scientists namely, Embden, Meyerhof and Paranas. On their names, glycolysis is also called E.M.P. pathway.

A petiole is the stalk or stem that connects the leaf to the plant It is usually attached to the shoot at the node, subtending (attached beneath) the lateral meristem (axillary bud). On a compound leaf, the petiole extends from the stem to the first set of leaflets.It does not helps in the gaseous exchange 

Glycolysis takes place in the cytoplasm of cell and does not need oxygen. Its is a common process in all living beings. Glycolysis is also called E.M.P. pathway. There is a net gain of two ATP and two NADH molecules in glycolysis. It is a common stage in both aerobic and anaerobic respiration .

The atmosphere consists of 78% nitrogen. 

The compounds that are oxidized during aerobic respiration are known as respiratory substrate which releases the entire energy available in the glucose.

All the above mentioned three structures helps in the gaseous exchange.

ATP- Adenosine Tri-Phosphate is a highly energetic molecule which is generally known as energy carrier of the cell. This chemical compound is very significant in biology as it stores the high amount of energy required for the vital functions of the cell. The energy released in respiration is stored in in the form of ATP

The windpipe is also known as trachea.It joins the the the upper respiratory tract to the lungs. If you gently touch the front of your throat you can feel the trachea. The bottom of the trachea splits into two branches called bronchi. One enters the right lung and one goes to the left lung.

In phylum Arthropoda, different types of respiratory organs had evolved. In terrestrial arthropods book lungs and trachea developed.In scorpions and spiders, respiration takes place by book lungs.

Lime water is a saturated solution of calcium hydroxide Ca(OH)₂ produced by mixing hydrated lime with water.It turns milky by CO₂  gas 

In simple multicellular animals, such as, sponges, cnidarians, etc., each cell of the body remains in contact with the environment (water) and thus, exchange of gases takes place through the surface of the cell by diffusion.

The human rib cage, also known as the thoracic cage, is a bony and cartilaginous structure which surrounds the thoracic (chest) cavity and supports the pectoral (shoulder) girdle, forming a core portion of the human skeleton. A typical human rib cage consists of 24 ribs, the sternum, costal cartilages, and the 12 thoracic vertebrae. The human rib cage is a component of the human respiratory system. It encloses the thoracic cavity, which contains and protects  the lungs.

Glycolysis takes place inside the cytoplasm of the cell. The cytoplasm is the aqueous based solution inside a cell that has a variety of molecules solubilized in it. The contents of the cytoplasm include proteins, carbohydrates, nucleic acids, salts and a whole host of other soluble molecules.

Glycolysis converts one molecule of glucose into two molecules of pyruvate(pyruvic acid), it makes energy in the form of two net molecules of ATP. Four molecules of ATP per glucose are actually produced; however, two are consumed for the preparatory phase.So, the net gain of ATP molecules is 2.

The oxidation of pyruvic acid into CO2 and water is called Krebs cycle. This cycle is also citric acid cycle because the cycle begins with the formation of citric acid. This cycle is also called as tri carboxylic acid cycle or TCA cycle. This cycle occurs only in the presence of oxygen.It takes place in the mitochondrial matrix.

Glucose is the primary form of sugar stored in the human body for energy. It is a simple sugars so,it is sweet in taste and is broken down quickly in the body to release energy.

 Whenever we perform intense physical exercises, our muscles use anaerobic respiration and produces lactic acid. 

Anaerobic respiration occurs in the cytoplasm when no oxygen is present for the cell to continue respiration after glycolysis. There are two common forms of anaerobic respiration: Alcoholic fermentation & Lactate fermentation . 

Two pyruvic acid molecules are the end product of glycolysis per mono- saccharide molecule. So,pyruvic acid is the ultimate product of glycolysis.

When there is respiration through the aerobic process, Glucose together with Oxygen produces Energy, Carbon Dioxide and Water.A lot of energy is produced during aerobic respiration, which may be as high as 38 ATP molecules for every glucose molecule. This means that the cell stores energy in form of ATP.

Pneumatophores are erect roots that are some form of upward appendage or extension of the underground root system. Because these roots are exposed at least part of the day and not submerged underwater, the root system can obtain oxygen in an otherwise anaerobic substrate.These are known as breathing roots.

Vocal cords are structures in the larynx which are designed to vibrate when air passes by, producing sound. These structures allow people to speak, and they also help to protect the lungs from accidental inhalation of food, saliva, and mucus. 

Gills greatly increase the surface area for gas exchange and they occur in a variety of animal groups including arthropods (including some terrestrial crustaceans), annelids, fish, and amphibians. 

The diaphragm is crucial for breathing and respiration. During inspiration, the diaphragm contracts , thus enlarging the thoracic cavity (the external intercostal muscles also participate in this enlargement).