What happens during the process of decay?

During the process of decay, the primary phenomenon occurring is decomposition, which involves the breakdown of organic matter. This breakdown is largely facilitated by enzymes, both from the body itself and from microorganisms, such as bacteria and fungi. These enzymes act on the tissues and biological molecules, leading to a gradual disintegration of the body's structure.

This natural process results in the release of gases and the further breakdown of organic compounds, which is essential for recycling nutrients back into the ecosystem. Hence, the correct answer highlights that decomposition is driven by enzymatic action, making it an integral aspect of decay.

The other options pose scenarios that do not accurately represent the decay process. For instance, the suggestion that the body remains intact contradicts the very essence of decay, which entails physical breakdown. Similarly, the idea of preservation without change is inconsistent with the concept of decay, as decay inherently involves transformation and deterioration of biological tissues. Lastly, while external factors can sometimes delay decay, this does not represent the natural process itself, which occurs in the absence of hindrances.