The autonomic nervous system has two divisions: The sympathetic division acts to energize the body, preparing it for action. The parasympathetic division acts to calm the body, allowing it to rest. Our everyday activities are controlled by the interaction between the sympathetic and parasympathetic nervous systems.
Update: N2Aos is now available for Kindle Fire HD and Kindle Fire HD 8.9. And you get the full Android experience here, including access to the Google Play store and all the other features offered by Android 4.2 (excepting what's not available via hardware, of course).
Fire OSâs Android roots provide Amazon with a large amount of apps that can be easily ported from Android and placed on the Amazon App Store. It also means they can push the Amazon App Store as a solution for other Android devices, competing directly with Google Play and selling Android apps to their customers.