Choose the one word or phrase that best completes the sentence. Click on the letter (A), (B), (C), or D in the answer space provided.

 

1 ------- are generated by air flowing out of the lungs.
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Virtually ------- species have biological clocks that regulate their metabolism over a 24-hour period.


 
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Viruses are ------- than cells and can be detected only with powerful electron microscopes.

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In computing, a support environment is ------- used to help people design and write other programs.

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For tens of thousands of years, fish ------- an important part of people’s diets.



 
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The metronome, ------- that serves to indicate the tempo of a piece of music, was invented in the seventeenth century.



 
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On April 17, 1610, Henry Hudson set out in the 55-ton ship Discovery on ------- fourth voyage of exploration.



 
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Sulfur, ______ most elements lighter than iron, is believed to have been created by the nuclear fusion of lighter elements in the interior of stars.



 
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The fluoroscope makes ______ for medical doctors to view a silhouette of the bones and internal organs of a patient’s body.



 
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Elementary schools in the United States provide formal education ______ arithmetic, science, social science, and communication skills that include reading, writing, spelling, and speaking.



 
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Democratic governments constantly face the problem of balancing ______ the individual with the needs of society.



 
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11 Not until the First World War ------- to improve the road system in the United States.
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12 An unconsolidated aggregate of silt particles is also termed silt, -------- a consolidated aggregate is called siltstone.
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13

In jazz music, a riff is a simple melodic figure, ------- and repeated several times.

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14

------- highly elliptical orbit of Mars carries it as far as 155 million miles from the Sun and as close as 128 million miles.


 
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------- highly elliptical orbit of Mars carries it as far as 155 million miles from the Sun and as close as 128 million miles.


 
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