Which part of the united states contains higher elevation, the southeast or the northwest?

I believe the answer is: Northwest

This difference in elevation would also cause the difference in climate between the two region and create a distinction between the type of agriculture that could thrive in each regions. 
The northwest region is perfect for plants such as soybeans and canola to grow while the warmer southeast region is perfect for plants such as potatoes, wheat, and onion.

Multiplying frequency by period