Oxygen help in combustion of substance by oxidising the carbon substance into carbon dioxide gas....so the correct answer is B.

Combustion and Burning

Combustion is a chemical reaction that occurs when a substance combines rapidly with oxygen, resulting in the release of heat and light. This process is commonly known as burning. The substance that undergoes combustion is called a fuel. In order for combustion to occur, three things are required: fuel, oxygen, and heat.

The Role of Oxygen in Combustion

Oxygen is a crucial component in the process of burning. It acts as an oxidizing agent, meaning it combines with the fuel to produce new substances. During combustion, the oxygen molecules break apart and react with the fuel molecules, releasing energy in the form of heat and light. This reaction is called oxidation.

Materials that Burn

Not all materials are capable of undergoing combustion. Only certain substances, known as flammable or combustible materials, have the ability to burn. These materials have a high affinity for oxygen and can react quickly with it. One such material is carbon-based fuels, such as wood, coal, and gasoline. However, the most common element involved in combustion is hydrogen, which when combined with oxygen, produces water.

Explanation of the Correct Answer

The correct answer to the question is option 'B': oxygen. Oxygen is the primary component required for combustion to occur. It is highly reactive and readily combines with other substances, including fuels, to release energy. This is why oxygen is considered the most important element in the process of burning. Without oxygen, combustion cannot take place, and the material will not burn.

Other Options

- Hydrogen: While hydrogen is highly flammable, it is not the correct answer because it is not the substance that combines with fuels during combustion. Instead, hydrogen itself combines with oxygen to produce water.
- Carbon: Carbon is a component of many fuels, but it is not the substance that combines with oxygen during combustion. Carbon-based fuels react with oxygen to produce carbon dioxide and water.
- Water: Water cannot combine with other substances to cause combustion. In fact, water is often used as a fire extinguishing agent to cool down and remove heat from burning materials.

Therefore, option 'B' (oxygen) is the correct answer as it is the substance that combines quickly with a material during combustion, resulting in burning.