Explain the use of Go interfaces for designing loosely coupled systems?

In Go, interfaces define a set of methods that a type must implement in order to satisfy the interface. This allows for abstracting away the details of how a type performs a certain behavior, and instead, focus on the behavior itself. This is particularly useful for designing loosely coupled systems, where the different components of a system can interact with each other through interfaces, without having to know the specifics of each other's implementation.

By using interfaces, a developer can define a common set of methods that different types can implement, allowing for polymorphism in the code. For example, if we define an interface called **Animal** with a **Speak** method, any type that implements the **Speak** method can be considered an **Animal**, regardless of its specific type. This allows for more flexibility and extensibility in the code, as new types can be added and used in the same way as existing types that implement the same interface.

Interfaces can also be used for dependency injection, where a component's dependencies are defined as interfaces rather than concrete types. This allows for more modular and testable code, as the dependencies can be easily swapped out with mock implementations for testing purposes.

Overall, Go interfaces are a powerful tool for designing flexible and extensible systems, allowing for loose coupling and polymorphism in the code.