Android is a mobile operating system based on the Linux kernel. It is the most widely used smartphone OS in the world. Google acquired Android Inc. in 2005 and has since developed Android with the goal of providing an open and flexible mobile platform. There have been over 200,000 apps developed for Android, which are primarily written in Java. Major versions of Android include Cupcake, Donut, Eclair, Froyo, Gingerbread, Honeycomb, Ice Cream Sandwich, Jelly Bean, KitKat, Lollipop, Marshmallow, and Nougat. Android offers advantages like multitasking and access to thousands of apps but also disadvantages such as requiring an internet connection and occasional security issues.