<ol>
<li><p>It was a war, we were using all our military technology to fight the aliens. The only thing is that the way ended in an unexpected way.</p></li>
<li><p>The aliens got sick from the bacteria/micro-organisms that live on the earth. I actually liked it, it's kind of ingenius that they would die in such a way considering how technologically advanced they were.</p></li>
<li><p>Don't Know</p></li>
<li><p>That one was simple. I think they were changing the starter? And that's the only computer piece in the whole car. so when the whole electromagnetic pulse or whatever went off, it didnt even have a starter in its car b/c they were switching it out with a new one.</p></li>
<li><p>Prolly fuel.</p></li>
<li><p>They were probably planning, observing -- or waiting for an optimal time to attack us. They could live for 1 billion years, it doesn't matter. Because they dont live on earth they naturally did not have the resistance. </p></li>
</ol>
<p>I heard the movie was fairly in line with the book.</p>