Burning (oxydation, reaction with oxygen) is possible only when oxygen exist.
no
When propanol is heated over a copper catalyst in the absence of oxygen, the primary products formed are propene (an alkene) and water. This process involves the dehydration of propanol to form propene.
Possible products of respiration in the absence of oxygen are lactic acid, ethanol, and carbon dioxide. This process is known as anaerobic respiration and occurs in the absence of oxygen to produce energy.
they will enter the Krebs cycle
Energy and lactic acid (lactate).
lactic acid
Glucose and molecular oxygen - O2.
Hydrogen and oxygen
When hydrogen peroxide decomposes, it forms water and oxygen gas as products.
During photosynthesis, by-products like oxygen and water are formed. Oxygen is released into the atmosphere as a waste product of the light-dependent reactions, while water is produced as a result of the splitting of water molecules in the light-dependent reactions.
Basically Fermentation is an Anaerobic respiration (i.e. Oxidation of energy compounds in the absence of oxygen).That means the answer to your question is 'oxygen'.
When metals burn in oxygen, they form metal oxides. For example, when iron burns in oxygen, it forms iron oxide (rust). The specific metal oxide formed depends on the metal and the conditions of the reaction.