Scientists estimate there are 14 million to 100 million species on earth. They have identified only about 2 million. Why haven't they identified more?
A. We have not devoted the resources to identifying them.
B. The total number of species changes quickly over a few years.
C. The total number of species varies with the seasons.
D. It is hard to keep count because of a rapid increase due to genetic engineering.
Answer: A
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In the world map below the color that represents soils that swell and shrink excessively is
A) pink.
B) light green.
C) medium blue.
D) purple.
Environmental policies and regulations are approved at the ________
A) state and federal levels B) local level only C) local, state, and federal levels D) federal level only
Between each period of maximum ice advance, known as a glacial period, a warmer time called a(n) _______________ period occurred
Fill in the blank(s) with correct word
What type of magmas have high silica content and tend to cause violent volcanic eruptions?
A. intermediate B. mafic C. felsic D. andesitic E. lava