What factors lead to the U. S. becoming a world power? * Abundant natural Resources, rich soil and temperate climate suitable for farming.
A vast and efficient system of waterways to transport goods.
Westward migration and immigration from Europe.
All of the above.

Answer (d) may increase or decrease porosity through dissolution or deposition;

A

Ithink the best answer is d increased stability of all other biomes

The first immigrants to settle in what is now the united states were the ancient ancestors of modern native americans. the precise routes of those first north american immigrants are disputed, but there is no uncertainty about the fact that every human being on the continent is either a recent immigrant or a descendant of earlier immigrants. since the first immigrants came here from asia more than thirteen thousand years ago, there have been four large and easily recognizable modern waves of immigrants into the united states.