Nitrogen is special because it is necessary for growth and reproduction. It's needed for plants and animals to survive. The main function for the atmosphere i believe is to give oxygen and nitrogen.
<span>There are no choices given, but the event was most likely a physical one that would have barred the squirrels from seeing each other. Squirrels are a social creature, and the event that would have separated the populace could have been anything from a large fire to an earthquake that separated the squirrels from each other.</span>
I believe the answer is Integumentary, Hope this helps ")
