title: How an Activity is killed by Android?
body: <p>As we know <em>Android</em> would kill a paused <em>Activity</em> in some conditions. And there is a FIFO back stack of <em>Activities</em>.</p>
  
  <p>My questions are as follows: </p>
  
  <ol>
  <li><p>How Android kills an <em>Activity</em> without pulling it from the back stack (it might affect the top active <em>Activity</em>)</p></li>
  <li><p>After killing it, what things are released from this <em>Activity</em>? And can I still get this <em>Activity</em>'s instance?</p></li>
  </ol>