Answer: After the unification of the Arab tribes, Islam expanded in all directions. Within a few decades, it occupied an area of land only comparable to the Roman Empire in its heyday. It would soon assume the role of commercial liaison between economically important areas of the world then: in Europe, Africa and Asia. The military progress achieved by the Muslims allowed them to isolate Europe, blocking trade especially through control of the Mediterranean Sea. For many historians, this has accentuated a trend that had existed since the 5th century, focused on agrarian life, and which would lead Europe to feudalism.
The Islam changed because of these encounters, with technology, some traditions and religions were swept away or changed.
<span>Mountains created cultural divides between civilizations </span>
The world's population today is much larger than it has been in anytime in the history of the world, and has been continuing to grow ever since the Industrial Revolution, since this raised the living standards and increased in incomes of an enormous number of people, especially in the western world. Advances in medicine have also played a major role.
Was the United States rationalize in going on to the war this Mexico?
I’m not sure if this is what you meant!