Whats the diff between the core and extended

[pantaloonz2]

Greetings,

I'll make no bones about it, I'm definately a newb, I did get 3.5 working on my phone, sort of flying blind. I've read numerous posts but I still have a fundamental understanding missing.

1. What's the difference between the core and extended?

2. Can you just flash a core rom with no extensions

3. If #1 is true, what does a core rom by itself generally consist of?

4. I'm thinking that these kitchens all include some sort of base, or core rom, how do I identify what that is?

Thanks in advance for info

Pantz