PhoneGap

Developing in the mobile space can be a daunting task for developers.  Developers must figure out which platforms they should support for their apps, purchase the hardware, and join the developer programs for each platform.   PhoneGap is an open source set of tools which enables developers to create mobile applications for multiple devices by utilizing the same code. It is a hybrid mobile application framework that allows the use of HTML, CSS, and JavaScript to write applications which are based on the open standards of the web.  MonoTouch and Mono for Android rely on the Mono Framework to function. Mono is a cross-platform open source implementation of the .NET Framework.  Mono is a cross-platform open source implementation of the .NET Framework. 

How is sharing code being one of the most appealing reasons to use MonoTouch and Mono for Android?  Explain
How is the use of debugging tools helpful in resolving mobile application issues quickly?