It sounds like you’re asking about a specific biochemical process and which additional molecule is required for it to proceed. To give a precise answer, I need to know which process you’re referring to (for example, cellular respiration, photosynthesis, or a particular enzymatic reaction). Different processes require different cofactors or substrates. If you’re thinking about a common cellular process, a frequent follow-on question is:

• In cellular respiration, what other molecule is needed alongside glucose for aerobic energy production? The answer is oxygen, which serves as the final electron acceptor in the electron transport chain, enabling efficient ATP generation.

Please share the exact process or the reaction you have in mind, and I’ll identify the critical cofactor or co-substrate that must be present for that process to occur.