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).
Lightning Web Browser for Android review. Lightning's Android Web browser is open source, includes a built-in ad blocker in the paid version, and puts many other browsers to shame when it comes to security and privacy. Firefox for Android supports add-ons, custom search, data syncing, and more.