Sierra Madre, mountain system of Mexico<span>. It consists of the Sierra Madre Occidental (to the west), the Sierra Madre Oriental (to the </span>east<span>), and the Sierra Madre del Sur (to the </span>south<span>). </span>
Answer:
to move from one place to another
Explanation:
Thermosphere is the answer
A contour line consists of points that are all at the same elevation, and each line has a different elevation. If two lines crossed, the point where they cross would be a point on both lines, so it would be a point that has two different elevations. That can't exist.
Answer:
The land was so fertile because of the big amounts of silt that the rivers brought to their shores.
Explanation:
The river valleys of Tigris and Euphrates in the Middle East, and the Nile in Northern Africa, were the places were the two earliest civilizations arose. These two civilizations were Sumer and ancient Egypt. The main reasons why these two civilizations developed were exactly the aforementioned rivers and their valleys.
Tigris and Euphrates on one side, and the Nile on another side, were bringing in enormous amounts of silt to their shores each year. The silt was making the river valleys highly fertile, which in turn meant that the people can engage in large scale agricultural production. Because the people had good conditions for the big production of agricultural goods their food supplies were guaranteed, so they were able to specialize in other fields and gradually develop into real civilizations.
