What is .Net Framework?

Answer 1

"A programming infrastructure created by Microsoft for building, deploying, and running applications and services that use .NET technologies, such as desktop applications and Web services.

The .NET Framework contains three major parts:

 * Common Language Runtime

 * Framework Class Library

* ASP.NET.
"

C# , VB .NET designed to run on .NET framework

Answer 2

Yes, Using Xamarin
https://www.xamarin.com/getting-started/android

Answer 3

Can you make mobile apps with C#?

Answer 4

Thanks brother