Which process involves bringing sections to water after dehydration?

The correct process that involves bringing sections to water after dehydration is hydration. In histology, after tissues are processed and embedded, they undergo a series of steps that include dehydration, where water is removed from the tissue, typically using alcohol. Once the dehydration step is completed, the next phase is hydration, where the tissue sections are reintroduced to water. This is crucial for the proper staining of tissues as it prepares them for the staining process by restoring their structure and enabling better interaction with the stains used for microscopic examination.

The other processes mentioned are distinct and serve different purposes. Embedding refers to the process of encasing the tissue in a medium (often paraffin) to provide support for cutting thin sections. Fixation is the process of preserving biological tissues in a state as close to their in vivo condition as possible through chemical means. Deparaffinization is a step that occurs when removing the embedding material (paraffin wax) from the sections prior to hydration and staining. Each of these processes plays a critical role in tissue preparation, but hydration specifically addresses the need to reintroduce water into dehydrated sections.