Answer: Combustibility refers to how reactive a substance is with oxygen.
Step-by-step explanation:
Combustibility is a measure of a substance's ability to burn or ignite when exposed to oxygen. Substances that are highly combustible are more reactive with oxygen and are more prone to catching fire or burning. Some common examples of combustible substances include wood, paper, and gasoline.
Reduction, on the other hand, refers to a chemical reaction in which a substance gains electrons or hydrogen atoms, or loses oxygen atoms. Reduction reactions are the opposite of oxidation reactions, in which a substance loses electrons or hydrogen atoms, or gains oxygen atoms. Reduction and combustibility are not directly related to each other.