An example of an exclusive power is when .

1) a local government collects taxes from a foreign business
2) the United States signs an arms control treaty with another country
3) a state allows a foreign business to operate a manufacturing plant in a city

the United States signs an arms control treaty with another country

Explanation:

The option your looking for is 2) The United States signs an arms control treaty with another country

these conditions long with a short growing season made farming difficult.

explanation:

the north has a climate of warm summers and snowy cold winters. the terrain is rocky, hilly, and not good for farming.