Final answer:
The advantage of multi-tier architecture over the two-tier architecture is the enhancement of reusability and scalability by adding the middle tier.
Step-by-step explanation:
The advantage of multi-tier architecture over the two-tier architecture is the enhancement of reusability and scalability by adding the middle tier. In the two-tier architecture, both the presentation and data layers are combined, making it difficult to make changes without affecting the entire system. On the other hand, in the multi-tier architecture, the business logic is separated into different layers, allowing for modular development and change. Any business-related changes can be made only to the front-tier without affecting the other tiers. This improves flexibility and maintainability by allowing different tiers to be developed, deployed, and scaled independently.