jbogarthyde · Jun 13, 2018 · Jun 25, 2018 · trotyl · Jul 11, 2018 · jbogarthyde
diff --git a/aio/content/guide/architecture-components.md b/aio/content/guide/architecture-components.md
@@ -8,9 +8,10 @@ A _component_ controls a patch of screen called a *view*. For example, individua
 * The list of heroes.
 * The hero editor.
 
-You define a component's application logic&mdash;what it does to support the view&mdash;inside a class. The class interacts with the view through an API of properties and methods.
+You define a component's application logic&mdash;what it does to support the view&mdash;inside a class.
+The class interacts with the view through an API of properties and methods.
 
-For example, the `HeroListComponent` has a `heroes` property that returns an array of heroes that it acquires from a service. `HeroListComponent` also has a `selectHero()` method that sets a `selectedHero` property when the user clicks to choose a hero from that list.
+For example, the `HeroListComponent` has a `heroes` property that holds an array of heroes. It also has a `selectHero()` method that sets a `selectedHero` property when the user clicks to choose a hero from that list. The component acquires the heroes from a service, which is a TypeScript [parameter property[(http://www.typescriptlang.org/docs/handbook/classes.html#parameter-properties) on the constructor. The service is provided to the component through the dependency injection system.
 
 <code-example path="architecture/src/app/hero-list.component.ts" linenums="false" title="src/app/hero-list.component.ts (class)" region="class"></code-example>
 
@@ -39,8 +40,7 @@ Angular inserts an instance of the `HeroListComponent` view between those tags.
 
 * `templateUrl`: The module-relative address of this component's HTML template. Alternatively, you can provide the HTML template inline, as the value of the `template` property. This template defines the component's _host view_.
 
-* `providers`: An array of **dependency injection providers** for services that the component requires. In the example, this tells Angular that the component's constructor requires a `HeroService` instance
-in order to get the list of heroes to display.
+* `providers`: An array of **dependency injection providers** for services that the component requires. In the example, this tells Angular how provide the `HeroService` instance that the component's constructor uses to get the list of heroes to display.  
 
 <hr/>
 

diff --git a/aio/content/guide/architecture-modules.md b/aio/content/guide/architecture-modules.md
@@ -88,7 +88,8 @@ For example, import Angular's `Component` decorator from the `@angular/core` lib
 
 <code-example path="architecture/src/app/app.component.ts" region="import" linenums="false"></code-example>
 
-You also import NgModules from Angular _libraries_ using JavaScript import statements:
+You also import NgModules from Angular _libraries_ using JavaScript import statements. 
+For example, the following code imports the `BrowserModule` NgModule from the `platform-browser` library:
 
 <code-example path="architecture/src/app/mini-app.ts" region="import-browser-module" linenums="false"></code-example>
 

diff --git a/aio/content/guide/architecture-services.md b/aio/content/guide/architecture-services.md
@@ -60,11 +60,29 @@ The process of `HeroService` injection looks something like this:
 
 ### Providing services
 
-You must register at least one *provider* of any service you are going to use. You can register providers in modules or in components.
+You must register at least one *provider* of any service you are going to use. A service can register providers itself, making it available everywhere, or you can register providers with specific modules or components. You register providers in the metadata of the service (in the `@Injectable` decorator), or in the `@NgModule` or `@Component` metadata 
 
-* When you add providers to the [root module](guide/architecture-modules), the same instance of a service is available to all components in your app.
+* By default, the Angular CLI command `ng generate service` registers a provider with the root injector for your service by including provider metadata in the `@Injectable` decorator. The tutorial uses this method to register the provider of  HeroService class definition:
 
-<code-example path="architecture/src/app/app.module.ts" linenums="false" title="src/app/app.module.ts (module providers)" region="providers"></code-example>
+``` 
+@Injectable({
+  providedIn: 'root',
+})
+``` 
+
+ When you provide the service at the root level, Angular creates a single, shared instance of HeroService and injects into any class that asks for it. Registering the provider in the `@Injectable` metadata also allows Angular to optimize an app by removing the service if it turns out not to be used after all. 
+
+* When you register a provider with a [specific NgModule](guide/architecture-modules), the same instance of a service is available to all components in that NgModule. To register at this level, use the `providers` property of the `@NgModule` decorator:
+
+``` 
+@NgModule({
+  providers: [
+   BackendService,
+   Logger
+ ],
+ ...
+})
+``` 
 
 * When you register a provider at the component level, you get a new instance of the
 service with each new instance of that component. At the component level, register a service provider in the `providers` property of the `@Component` metadata: