Answer may be:

The folders along with the description:

• gen: gen contains the compiled .R generated files that point out all the resources of the project.
• src: It holds .java source files in our project. 
• bin: It contains the .apk file built by the android development tool as well as those things also that are not needed to run the android application.
• AndroidMainfest.xml: It explains all the features of the application and the definition of the components.
• res/values: It has value files such as color, strings, and the theme file of the project.
• res/drawable: This directory has drawable and different screen XML files.
• res/layout: This directory has the layout files of each activity.