Why did the Android developers decide against using the existing desktop and web application models?

Why did the Android developers decide against using the existing desktop and web application models? (Mark all that apply.)

Note: Make sure you select all of the correct options—there may be more than one!

1. The desktop model did not offer sufficiently flexible data sharing between applications
2. The desktop model did not offer sufficient isolation between applications
3. The web application model made installing an application too difficult
4. The web application model did not offer sufficient functionality, at the time Android was being developed