Please help Contrast the borderlands between the US and its northern and southern neighbors, i. e. the US-
Canada borderland and the US-Mexico borderland respectively. How are the differences related to
economic, social and physical geographic features?

Magma forms by partial melting of upper mantle and crust. partial melt means that only a fraction of the available material forms a melt, and that the remainder stays solid. the partial melt rises because of its lower density and ascends through he crust. this is so conclusive mean the answer would be magma igneous rocks or balistic magma.