GED Science Practice 2025 – 400 Free Practice Questions to Pass the Exam

A substance that initiates or accelerates a chemical reaction without being consumed or permanently altered in the process is known as a catalyst. Catalysts work by providing an alternative pathway for a reaction that has a lower activation energy, making it easier for the reaction to occur. This ability allows them to increase the rate of a reaction significantly without undergoing any changes themselves, meaning they can be used repeatedly in multiple reaction cycles.

In contrast, carcinoma refers to a type of cancer, which is unrelated to chemical processes. Carnivores are animals that primarily eat meat, which is more related to biology and ecology than to chemical reactions. A cathode is an electrode through which current flows into a polarized electrical device, playing a role in electrochemical reactions, but it is not involved in initiating or accelerating chemical reactions in the same way a catalyst does. Thus, the nature and function of a catalyst make it the correct answer in the context of this question.