Answer:

Introduction:
The burning of fire is a chemical reaction that occurs when a substance undergoes combustion in the presence of oxygen. Fire is a rapid oxidation process, which releases energy in the form of heat and light. Oxygen is a key component required for burning to occur, making option 'A' the correct answer.

Explanation:
Oxygen:
- Oxygen is one of the essential components required for a fire to burn. It is necessary for the process of combustion because it acts as an oxidizing agent.
- When a substance burns, it reacts with oxygen atoms in the air, breaking the bonds between the atoms in the substance and releasing energy in the process. This energy is what we perceive as heat and light.
- Without oxygen, the fire cannot sustain itself, and the burning process will cease.

Carbon Dioxide:
- Carbon dioxide (CO2) is produced as a byproduct of combustion. When substances burn, carbon compounds present in them combine with oxygen to form carbon dioxide.
- While carbon dioxide is released during the burning process, it is not a requirement for the fire to continue burning. In fact, excessive amounts of carbon dioxide can even extinguish a fire by displacing oxygen.

Nitrogen:
- Nitrogen is a major component of air, making up approximately 78% of the Earth's atmosphere. However, nitrogen does not support combustion and is not involved in the burning process.
- Even though nitrogen is present in the air, it does not contribute to the fire and is not necessary for the fire to burn.

Water Vapour:
- Water vapor is produced as a byproduct of combustion when a substance containing hydrogen and oxygen atoms burns.
- While water vapor is released during the burning process, it is not a requirement for the fire to continue burning. In fact, excessive amounts of water vapor can potentially extinguish a fire by absorbing heat and displacing oxygen.

Conclusion:
In conclusion, the burning of fire requires oxygen as it is an essential component for the combustion process. While carbon dioxide and water vapor are produced as byproducts of combustion, they are not necessary for the fire to continue burning. Nitrogen, on the other hand, does not support combustion and is not involved in the burning process.

Oxygen