There are many factors that affect the microeconomic benefits of tourism, among which the uncontrollable factor is (). [2009 Zhenti]

There are many factors that affect the micro-economic benefits of tourism, but from the perspective of the control ability of tourism enterprises, the factors that affect the micro-economic benefits of tourism can be divided into two categories, one is the internal factors that tourism enterprises can control, and the other is the external factors that tourism enterprises can't control, both of which will have an impact on the micro-economic benefits of tourism. Uncontrollable factors include: ① the balance between the scale of tourism demand and time; ② Tourism economic management system; ③ External economy.