The correct answer is - carving terraced farmlands.
The Incas revolutionized the agriculture in South America by starting to use the carved terraces for production. With this technique, the Incas managed to maximize the arable land area, and to perform farming on places where naturally will be impossible. This method is widely used nowadays, and since the amount of arable land is reducing in the lowlands, it is of great benefit for food production in places that are not suitable for building.
Austria-Hungary was a nation of many different nationalities. If each ethnic group became an independent nation, there would be no more Austria-Hungary. Therefore, the nationalists were a threat to Austria-Hungary because if they took action, the empire would fall apart.
Answer: 
Explanation:
We are asked to multiply 1 nano sec with 1 km/sec.
The conversion used from nano second to second
1 nsec = 
The conversion used from km to meters:
1 km = 1000 m

Putting the values we get:

Therefore, the given conversion is 
Oil tourism should be tha right one because there famous for the oil