Are you a developing an Android App and require to know the minimum support version on Android Studio ?
The minimal support version of the Android OS that you select in Android Studio directly correlates to the Version of Android API on an Android Phone.
The API version controls what functionalities (as provided for by the API) are available on an Android device.
en.wikipedia.org/wiki/Android_version_history
While developing an App, selecting a version of Android (eg 7.0 is Android Nougat) enables you to use functionalities (upto API level 24 in Android Nougat) for your App development.
The downside, logically is that an app developed for Android Nougat with API level 24 will not deploy on an Android device whose OS version is < 7.
Hence the reason why in the Android App config, you have to select a minimum version of the API so that your app can be deployed on devices that were shipped with an earlier Android OS version (Kitkat - API 19-20, Lollipop API 21-22).
Once you select an Android Version as minimal support version , you also need to download the corresponding SDK platform and build tools for that version.

One hack for testing purposes is to change the minSDKVersion in your App Config (build.gradle) and deploy the app on a android device with a earlier legacy version of Android like JellyBean (Version 4.x API Level 16) or Kitkat (Version 4.x API 19-20) to see if your code base will build for older devices.
