Which one of the following gases is supporter of combustion?

Combustion is a chemical process in which a substance reacts with oxygen to give off heat. Oxygen is fundamentally recognized as the primary supporter of combustion [3]. It is one of the three essential components of the 'fire triangle,' alongside fuel and heat [5]. While oxygen itself is not flammable, its presence is mandatory for a combustible substance to burn; limiting the supply of air (and thus oxygen) results in incomplete combustion [4]. In contrast, nitrogen is a relatively inert gas that acts as a non-supporter by diluting oxygen to control or prevent spontaneous combustion [2]. Carbon dioxide is also a non-supporter and is commonly used in fire extinguishers to smother flames by displacing oxygen [5]. Hydrogen is a combustible substance (fuel) rather than a supporter of the combustion process itself [3].

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 5: Changes Around Us: Physical and Chemical > Is the Presence of Air Enough for Combustion? > p. 63
2. [3] Science-Class VII . NCERT(Revised ed 2025) > Chapter 5: Changes Around Us: Physical and Chemical > 5.3.2 Combustion > p. 62
3. [5] Science-Class VII . NCERT(Revised ed 2025) > Chapter 5: Changes Around Us: Physical and Chemical > Activity 5.6: Let us investigate > p. 64
4. [4] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Activity 4.4 > p. 69
5. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Nitrogen > p. 272