Which process involves separating a complex item into simpler components?

The process that involves separating a complex item into simpler components is known as decomposition. Decomposition is a fundamental concept in various fields, including computer science, mathematics, and systems engineering. It allows for a better understanding of the components that make up a complex system by breaking it down into manageable parts. This simplification aids in analysis, as it is often more efficient to study the individual components rather than the entire system at once.

In contrast, integration refers to combining parts to form a whole, which is the opposite of decomposition. Analysis generally involves examining or studying something in detail, but it does not specifically imply breaking it down into simpler components. Reconstruction, meanwhile, pertains to the process of rebuilding or assembling parts back into a complex item, which again is not aligned with the act of separating components. Thus, decomposition stands out as the correct term for this particular process.