Explain a factor that accounts for contemporary population growth.

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.

Ineed you to put up a picture of the map so i can you as much as possible.

The answer to your question is d. convection currents. hope this you.