I'm not sure exactly what unit you're referring to, but three of the main factors that affect oil prices today would be natural disasters, futures trading, and global demand.
a) tobacco because farmers don't grow it
By "commonwealth" it must be understood all along to mean not a democracy, or any form of government, but any independent community which the Latins signified by the word civitas, to which the word which best answers in our language is "commonwealth," and most properly expresses such a society of men which "community" does not (for there may be subordinate communities in a government), and "city" much less.
hopefully this helps!
