MVC vs KVO in implementation

I am a beginner in the realm of cocoa and don't understand when you should choose key value observing over the Mode开发者_StackOverflow中文版l View Controller. My question: Can everything that is done with a MVC scheme also be implemented with KVO? Is it true as well that you could replace any KVO with a similar MVC?

Thanks

They are not mutually exclusive. MVC is a general design pattern and KVO is a specific Cocoa technology which you can use in MVC applications (and other apps too).