Final answer:
Gap junctions are the cell junctions that best facilitate the coordinated beating of heart muscle cells.
Step-by-step explanation:
The cell junctions that would best facilitate the coordinated beating of heart muscle cells are gap junctions. Gap junctions are specialized protein channels that allow for direct communication and electrical coupling between adjacent cells. Through these gap junctions, ions and small molecules can pass freely between heart muscle cells, enabling them to synchronize their contractions and beat in a coordinated fashion.
Learn more about Coordinated beating of heart muscle cells