*** This principle states that **a class should only have one responsibility, or one reason to change**; used by a single user role. How does this principle help us to build better software?  Let's see a few of its benefits: 1. **Testing** – A class with one responsibility will have far fewer test cases. 2. **Lower coupling** – Less functionality in a single class will have fewer dependencies. 3. **Organization** – Smaller, well-organized classes are easier to search than monolithic ones. *** **References**: - [A Solid Guide to SOLID Principles](https://www.baeldung.com/solid-principles#s)