All motors require
A. an armature.
B. a power source.
C. magnets of some kind
D. none of the above
Answer: B
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What are the major causes and effects of climate change?
What will be an ideal response?
Frost occurs when dew freezes
Indicate whether the statement is true or false
Many conservationists support returning top predators such as wolves and panthers to areas where they have been exterminated. Although some reintroductions have been made, the practice is controversial because these animals are
A) considered by some ranchers to be a threat to livestock and humans. B) being introduced into areas that have never had predators before. C) predators that feed on many other endangered species. D) carriers of diseases that may infect other species in the region.
We know from the Apollo missions and unmanned probes that the moon's surface is covered with loose, unconsolidated material with a texture similar to soil on earth. How did this material form on the moon?
A) The material is mostly volcanic ash ejected from volcanos that are no longer active. B) The loose material is mostly micrometeorite fragments and ejecta from impact craters, so is very different from soil on Earth. C) The material is produced by spalling from rock surfaces caused by the extreme heat-cold cycles as the moon rotates through a 1 lunar day, or approximately one Earth month. D) The same as Earth, but soils are ancient from a time when the moon still had an atmosphere and water.