What is the main hurdle to replacing our current energy system (based on gasoline and coal) with one based on hydrogen?
A. The hydrogen does not occur naturally.
B. We have not developed the technology to produce it.
C. Hydrogen is highly flammable.
D. We haven't yet invented a system to extract energy out of hydrogen.
Answer: A
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A. electric fields. B. magnetic fields. C. alternating current. D. electromagnetic induction.
Demand for health care and education has grown because
A) the aging baby boomers demand more health care services. B) increasingly sophisticated technology requires that workers be better educated. C) these services are so inexpensive. D) all of the above. E) A and B only.
What is the best-known and oldest deep-diving manned research submersible now in operation?
a. Trieste b. Jiaolong c. Challenger d. Alvin e. Shinkai
The trade wind inversion
A) is highest along the eastern margins of oceans. B) is unrelated to the height of the marine layer. C) promotes greater vertical cloud growth farther to the west. D) allows more convection as it decreases in height.