I think maybe there were some options that you didn't copy?
Else I can say that a letter written at the time of a historical event would be a primary source - as opposed to a secondary source which is written well after the relevant event.
Green building doesn't involve only buildings which are made out of completely organic materials but it also involves building things which are meant to last and with a strong emphasis on the green surroundings where you live and how you can incorporate these buildings into the environment.
To protect from invaders (Mongols)
It is a good service <span>provided by law enforcement organizations, such as sheriffs and police. Hope this helps !
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