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@@ -1,12 +1,25 @@
 ---
 title: Flutter Interview Questions
 ---
+* What is the difference between Stateless and Stateful Widget in Flutter? </br>
+   If a widget can change—when a user interacts with it, for example—it’s stateful.
+   A stateless widget never changes. Icon, IconButton, and Text are examples of stateless widgets. Stateless widgets subclass 
+   StatelessWidget.
+   A stateful widget is dynamic: for example, it can change its appearance in response to events triggered by user interactions or when    it receives data. Checkbox, Radio, Slider, InkWell, Form, and TextField are examples of stateful widgets. Stateful widgets subclass 
+   StatefulWidget.
+   A widget’s state is stored in a State object, separating the widget’s state from its appearance. The state consists of values that
+   can change, like a slider’s current value or whether a checkbox is checked. When the widget’s state changes, the state object calls
+   setState(), telling the framework to redraw the widget.
 
-* What is the difference between Stateless and Stateful Widget in Flutter?
-* Explain Stateful Widget Lifecycle?
-* When to use WidgetsBindingObserver?
+* Explain Stateful Widget Lifecycle? </br>
+   <a> https://flutterbyexample.com/stateful-widget-lifecycle </a>
+* When to use WidgetsBindingObserver? </br>
+  If we want to listen to the events of the app life cycle we implement a WidgetsBindingObserver interface in main screen's 
+  StatefulWidget next, we get the instance of WidgetBinding and add an observer to it.
+  <a> https://medium.com/pharos-production/flutter-app-lifecycle-4b0ab4a4211a </a>
 * What is a Flutter Tree Shaking?
-* What is a Spacer Widget?
+* What is a Spacer Widget? </br>
+   <a> https://api.flutter.dev/flutter/widgets/Spacer-class.html </a>
 * Difference between HotRestart and Hot Reload?
 * What is an Inherited Widget and list some examples?
 * Why is the build() method on State and not Stateful Widget?
@@ -29,4 +42,4 @@ title: Flutter Interview Questions
 * How would you access Stateful Widget properties from it's State?
 * What is InheritedWidget in Flutter?
 * Is there a suggested limit to the number of FloatingActionButtons a screen can have?. Give reason(s) for your answer
-* Mention two or more operations that would require one to use or return a Future?
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+* Mention two or more operations that would require one to use or return a Future?