Which rock type makes up approximately 90% of the Earth's crust?
A) metamorphic
B) rhyolitic
C) igneous
D) sedimentary
E) plutonic
C
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According to environmental writer Bill McKibbin, "the great environmental story of the United States, and in some ways, the whole world" is the
a. restoration of grasslands b. regrowth of forests c. production of biofuels on forest land d. restoration of aquatic ecosystems e. restoration of saguaro cactus stands
What does this map show about acid rain (low PH)?
A) California suffers from of high levels of acid rain.
B) The Gulf Coast suffers from the highest levels of acid rain.
C) The Northeast has high levels of acid rain.
Reserves, by definition, must be all of the following except
A. all rock types that are likely to host as yet undiscovered ore. B. exploitable with current technology. C. identified ore deposits. D. economically profitable to mine at present.
Why would astronomers be interested in placing a gamma ray detecting observatory in space?
A) to map high-energy electromagnetic waves from distant sources that would be blocked out or scattered by Earth's atmosphere B) to map gamma ray emissions from radioactive elements on Earth C) to detect nuclear weapons tests on Earth D) to map gamma ray emissions coming from the Sun