A student pointed me at the following URL that shows that the instantiation behavior of Android activities can be customized in an application's Android manifest file:
http://developer.android.com/guide/topics/manifest/activity-element.html#lmode
More information can be found here:
http://developer.android.com/guide/topics/fundamentals.html#acttask
Finally, here is documentation on the startActivityIfNeeded method that was mentioned by a student in lecture:
It appears that there is a lot of flexibility built into Android for customizing the behaviors associated with starting activities!