[Typo3-dev] Reusability of code, plugins, extensions

[Vikram Mandal]

Hi Everyone,

I am pretty new to Typo3. I have seem some of codes of extensions. I was 
wondering how does Tyop3 achieve reusability.
Say for example there is extension for country, now I would like to use it 
in one of my extension which is a database of Research Center in various 
countries. How do we take care of such situations?

Are there ways to talk to other extensions APIs,..

Thanks for your thoughts
- Vikram