Final answer:
Horizontal integration refers to the arrangement where two or more companies at the same channel level work together, such as merging to enhance efficiency or grow larger.
Step-by-step explanation:
The arrangement within a channel of distribution where two or more firms at the same channel level work together for a common purpose is known as horizontal integration. This type of alliance often occurs when firms merge to become more efficient, grow larger, acquire new product lines, eliminate rivals, or build a brand as strong as industry leaders like Coca-Cola or Pepsi. Horizontal integration can help companies achieve economies of scale and provide a competitive edge in the market. It is different from vertical integration, which involves companies at different stages of production merging to streamline processes and protect against the loss of suppliers.