A flammable vapor concentration that is too rich to ignite is _____.
a. Below the lower explosive limit
b. Above the upper explosive limit
c. Between the lower explosive limit and the upper explosive limit
d. Below the upper explosive limit
Answer: b. Above the upper explosive limit
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Shallow-focus earthquakes are generally the most destructive, because: __.
a. they contain higher energy b. they move vertically c. they are closer to the surface and most of the energy is released on the surface d. none of the above
In general, biodiversity is
A) fairly evenly spread among all of the major groups of animals and plants. B) accurately quantified for most ecosystems, especially in tropical regions. C) 75% plant species and 25% animal species. D) declining in the United States and around the world.
Which pattern of emigration from the Caribbean is LEAST likely to occur?
A) A Haitian migrates to Liverpool, England. B) A native of Suriname sets up housekeeping in Amsterdam, the Netherlands. C) A Cuban establishes residency in Miami, Florida. D) A citizen of Barbados settles in the London suburb of Brixton. E) A Puerto Rican moves to New York City.
Which of the following photographs depicts an igneous rock where the magma cooled slowly at first and then had fast cooling?
A. 
B. 
C. 
D. 