Which of the following are characteristics of a RESTful service?

A RESTful service is fundamentally built on a stateless communication protocol, and it adheres to a client-server architecture. This means that each request from a client to a server must contain all the information needed to understand and process the request. The server does not store any client context between requests, which is what characterizes the statelessness of REST.

In addition to being stateless, RESTful services follow a client-server architecture where the client is responsible for the user interface and user experience, while the server manages the data and business logic. This separation allows for independent evolution of both client and server sides.

While JSON is a common format used for responses in RESTful services, it is not an inherent characteristic of REST itself; REST can work with XML, plain text, or other data formats as well. Resources being exposed as URIs is also a hallmark of RESTful architecture but maintaining a strict format for URIs isn't a fundamental characteristic. Lastly, stating that RESTful services are database-driven is incorrect as REST can operate over various backends, not just databases, and the architecture allows interaction with services that do not use databases at all.