What reactant is absolutely required for terrestrial burning processes like a candle flame?
Answer
An oxidizer, typically gaseous oxygen
Chemical combustion is an oxidation reaction that requires an external reactant, almost always gaseous oxygen from the atmosphere, to combine rapidly with a fuel source.

#Videos
Brian Cox Answers How Stars Burn in Space | This Morning - YouTube
Ask John: How do stars burn? - YouTube
Related Questions
What is the fundamental mechanism that allows stars to generate light and heat?What reactant is absolutely required for terrestrial burning processes like a candle flame?What physical process describes the creation of heavier helium nuclei from hydrogen nuclei in a star's core?What principle explains how the slight mass difference during fusion becomes the star's energy output?What state of matter characterizes the solar core where fusion occurs?What temperature must the core of a star like our Sun reach to initiate hydrogen fusion?What inward force, generated by the star's mass, helps force hydrogen nuclei close enough for fusion?What maintains the long-term stability of a star while it is on the main sequence?If the Sun were a chemical fire, why would it cease shining in a vacuum?What is the estimated travel time for a photon created in the Sun's core to reach the visible surface?