Which elements are found in a high proportion in earth’s crust?
a. aluminum and iron
b. oxygen and silicon
c. calcium and sodium
d. potassium and magnesium

Which environment would most likely not contain fossils? a a thick deposit of cracked, dried mud b sediment deposited in a sandy river bed c intrusive rock formed from cooled magma d layers of sand accumulated for a century

The increase of pollutants from in mexico has raised concerns about garage to health and the environment

17. the soil erosion pictured here is the result of what? a. harvesting renewable resources at a rate greater than the sustainable yield b. a mudslide caused by excessive rains c. harvesting renewable resources at a rate lower than the sustainable yield d. the transition between geologic eras and eons