Between the Living and Unliving:
What differentiates a man, animal, or tree from a rock or water? If you think about it, you will be able to pinpoint the differences. Rocks do not reproduce, they do not die, and therefore they were never alive. But the line is not always that clear.
Learn about the differences between life and non-life at:
Image via NASA/Corbis
Fact via: http://www.pbs.org/newshour/rundown/2012/06/deadly-flu-paper-published-carl-zimmer-explains-h5n1-and-beyond.html