In a multicellular organism, it is cell-to-cell communication that allows the trillions of cells to coordinate activities, including during development and regeneration. The three stages of cellular communication include: reception, transduction, and response. This study determined the key steps of a cell communication pathway involved in salamander limb regeneration. After amputation of a front salamander limb, the severed axons retract within the stump and grow back along the nerve sheath. To elucidate the molecular mechanisms, the researchers set up a series of controlled experiments to determine the events in salamander limb regeneration. Drag the general cell communication steps of the regeneration experiment into the correct order.