How does elevation affect temperature?
The higher you go, the colder it gets. For example, it is colder in the mountains than on a plain or by the ocean
Which factor most likely causes two cities at the same elevation and latitude to have different yearly average temperature ranges?
Air moving from a higher elevation to a lower elevation can cause turbulence in the air stream increasing air speed at the base of an elevation drop. Air moving over water will drop in temperature causing moisture evaporation in to the atmosphere. In the winter this is sometimes called "lake effect snow"