Subject and verb change their position in statement and question.
statement
question
You are from Germany.
Are you from Germany?
We always use the short answer, not only "Yes" or "No". This sounds rude.
NOTE:
If the answer is "Yes", we always use the long form.
Example: Yes, I am.
If the answer is "No", we either use the long or the contracted form (short form).
Example: No, I am not - No, I'm not.
BUT:
BUT:
NOTE!