These north american countries attract a large number of immigrants due their high standards of living.

canada
greenland
mexico
u. s.

"Canada" and "U. S." are the two North American countries among the following choices given in the question that attract a large number of immigrants due their high standards of living. The correct options among all the options that are given in the question are the first and the fourth options.

Since wxyz is 4, halfof that would be 2.

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.