How does the poverty and political instability of Mexico affect the United States

A. Many Mexicans come to the United States illegally

B. Many Mexican villages are devoid of working-age males

C. both A and B

D. None of the above

In restoration ecology, why might it be challenging to return a damaged ecosystem to original its state/function? Why do scientists often select watersheds as an area to study energy and matter flows in'ecosystems?

The fossils of multicellular life forms observed in rocks a. are bones that have lithified into rock b. are found mostly in igneous rocks. c. are proof of the young age of the Earth. d. are no older than ~600 million years.

What feature indicated a period of heavy bombardment followed by a. of low bombardment in our solar system?

Which layer surrounds the center of the earth

List and describe the achievements of the Maya during the Preclassic and Classic periods.

Total land mass area of europe in square kilometres

The population density of the Philippines is 798 people per square mile. If many refuges arrive from a neighboring country how will they affect the population density? O A. Cannot be determined. O B. The population density will decrease. C.

Select all of the true statements about deep ocean currents. A. They form gyres. B. They transport heat across Earth's surface. C. They are known as "thermohaline circulation." D. They are caused by wind and Earth's rotation. E.

What is the difference between emigrate and immigrate?

What is the difference between high concentration and low concentration