4. Understanding the Error and Code Examples
   What does it mean?This error indicates that your Angular 6 project is unable to locate a crucial package called @angular-devkit/build-angular
5. Understanding `providedIn` with `@Injectable` for Effective Service Management in Angular
   Angular heavily relies on Dependency Injection (DI) for creating and managing relationships between components, services
6. Understanding the (selectionChange) Event in Angular Material's mat-select
   The mat-select component had a (change) event that you could use to listen for changes in the selected option.In Angular 6 and later (including Angular Material 6):
7. Angular 6 Environment Configuration: Best Practices and Options
   Angular applications often have different configurations for development, staging, and production environments.Environment variables store settings specific to each environment (e.g., API URLs