Final answer:
Gap junctions are the type of cell junctions that enable direct communication between cells by allowing the merging of their cytoplasm.
Step-by-step explanation:
The type of cell junction that allows cells to communicate directly via merging of cytoplasm is gap junctions. These junctions form channels that permit the transfer of ions, nutrients, and other substances that enable cells to communicate. This is in contrast to desmosomes and hemidesmosomes, which are types of anchoring junctions that provide mechanical stability to tissues by connecting cytoskeletal elements to the cellular matrix, and tight junctions that prevent the movement of substances through the space between epithelial cells.
While desmosomes and hemidesmosomes also connect cells, they do not facilitate the kind of direct communication that gap junctions enable.