which clue can be used to identify a chemical reaction as a decomposition reaction?\nthe reaction involves…

Brief Explanations:

A decomposition reaction is defined as a reaction where a single - reactant breaks down into two or more products. Involving oxygen is characteristic of combustion reactions in some cases, involving ions is common in many types of reactions like ionic reactions, and having a single product is not a feature of decomposition reactions.

Answer:

The reaction has a single reactant.