I have no idea, but I wouldn't use Wikipedia.. The "facts" on there aren't always true. That's why we aren't allowed to use it in my high school.
When the price of oil drops this usually means that OPEC or a major state within OPEC like Saudi Arabia, or Venezuela has increased the supply of oil leading to a drop in price. This is the current policy of the Saudi Government which has led to a drastic decline in oil prices over the last 3 to 4 months.
I predict some more animals will become endangered because they will be loosing their habitat.
Zhou Dynasty is the people who did that[