Hello everyone,

I've got a few questions, and hope that you could help me.

First question:
What's the difference between "developed" and "developing" countries? I have no idea about it, because I don't now the difference between "developed" and "developing".

Second question:
What's the meaning of the following sentence?
Their steel plants produce steel at twice the cost of imported steel.

Third question:
Would you please explain me the difference between the following words?
- economics
- economic
- economy
- ecnomical

Fourth question:
Would you please explain me the difference between the following words?
- politics
- policy

Fifth question:
What are "blue-collor" workers?
What are "white-collor" workers?


I know that this are many questions, but it would be very nice, if you could help me.

Thanks in advance,
Dany