What causes the little pops and ticking that can be heard in some furnaces before the blower comes on?
A) Small quantities of water in the gas
B) Mechanical rattles from an unbalanced indoor blower
C) Expansion of the heat exchanger as it heats up
D) Small concentrated pockets of gas that explode
C
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The stage was set for a cataclysmic shift in the course of history when
A. Europeans increasingly demanded less expensive goods from Asia. B. Africa was established as a source of slave labor. C. the Portuguese demonstrated the feasibility of long-range ocean navigation. D. the Renaissance nurtured a spirit of optimism and adventure. E. All of these are correct.
____________________ listening is defined as the ability to hear a message clearly, using your eyes and ears, and by completely concentrating.
Fill in the blank(s) with the appropriate word(s).
Symptoms of ____________________ deficiency are decreased appetite, muscular weakness, and a characteristic paralysis known as polyneuritis or beri-beri
Fill in the blank(s) with correct word
Decay is the biological oxidation of nitrogen for energy
Indicate whether the statement is true or false.