Contiguous simply means touching or sharing a border, according to Merriam-Webster. When it comes to the United States, contiguous refers to all of the states that touch one another, without another country or a body of water coming between them. These are sometimes also referred to as the lower 48 states.
.apk extension stands for android package file. It is a file format used to distribute and install applications.It includes the programm codes ,assets ,resourses ,certificates and manifest file. .Dex extensions stands for Dalvix Executable files.
Android application package (APK) is the package file format used by the Android operating system for distribution and installation of mobile apps and middleware. The files that contain the .apk file extension store the files that are needed to run a single Android application on an Android mobile device.