Life probably would never have emerged on Earth if the ancient atmosphere had been the same as the present one in regard to the content of ____.
A. carbon dioxide
B. hydrogen
C. oxygen
D. nitrogen
E. carbon monoxide
Answer: C
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The metabolic breakdown of specialized brown fat depots in certain animals is substantially increased during _____
A) acclimatization B) torpor C) evaporative cooling D) nonshivering thermogenesis E) shivering thermogenesis
Which of the following are formed during the dissociation of carbonic acid as it occures in the tissue capillaries.
A) Water B) Bicarbonate ions C) Hydrogen ions D) Cardon dioxide
A biologist uses a time machine to collect living material from 2 different time periods. Sample A is 3 billion years old and sample B is 1.5 billion years old. How would these samples differ?
A. Eukaryotic organisms would be absent from sample A. B. Eukaryotic organisms would be present in both samples but much more common in sample B. C. Prokaryotic organisms would be abundant in sample A but absent from sample B. D. Prokaryotic organisms would only occur in sample B.
How does phosphate enter the soil?
A. photosynthesis B. cellular respiration C. conversion in the atmosphere due to lightning D. precipitation from clouds E. weathering of rocks