Facebook Account Disabled For Adding Too Many Friends

Hello,

I understand that FB can disabled an account if that account adds too many people.
What I want to know is as below:

1. What is the limit of friends that we can add to a Facebook account?
2. When Facebook decides to disabled an account for adding too many friends, will it prompt a warning box?
3. How can we activate an account that has been disabled for adding too many friends?

Thanks in advance for feedback on the above matter.