Which type of agent is used primarily during the embedding phase of histopathology?

In the embedding phase of histopathology, the primary focus is on providing a medium that will support the tissue as it is processed and sectioned for microscopic examination. The embedding media serves this purpose by infiltrating the tissue specimens, filling any empty spaces and ensuring structural integrity.

This embedding medium typically consists of a paraffin wax or resin which, once hardened, allows for thin slicing of the tissue samples, facilitating clear observation of cellular and tissue architecture under a microscope. The choice of embedding media can greatly affect the quality of the resultant sections and the clarity of the histological features observed.

Other agents listed, such as fixatives, dehydrating agents, and staining agents, play distinct roles in the overall histology process. Fixatives preserve the tissue and prevent degradation, dehydrating agents remove water from the tissue prior to embedding, and staining agents are used after sections are cut to enhance visualization of the structures. However, none of these are used specifically in the embedding phase itself. The embedding media is the crucial component during this phase, making it the correct answer to the question.