In Chapter 2, you mention that When you click the Home button on the Android emulator (so that the activity is pushed to the background), the onPause() and onStop() events are fired. (the onDestroy() event is not called, indicating that the activity is still in memory). [implying onDestroy() method removes the object from memory]

Further, you mention that "an activity is destroyed when you press the Back button" and state is lost but on the next page, there is a note saying "Even if an application has only one activity and the activity is killed, the application will still be running in memory"

It is very confusing here, could you clarify the above note please? Thank you.