If early Earth's atmosphere contained little or no O2, then where did most of the O2 in our modern atmosphere come from?
A) Photosynthesis
B) The breakdown of carbon dioxide
C) The splitting of water vapor by sunlight
D) The oxidation of metals
E) Respiration
A
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The half-life of carbon-14 is 5,600 years. A fossil that has one-eighth the normal proportion of carbon-14 to carbon-12 is probably
A. 2,800 years old. B. 5,600 years old. C. 11,200 years old. D. 16,800 years old. E. 22,400 years old. Clarify Question What is the key concept addressed by the question? What type of thinking is required? Gather Content What do you already know about half-lives of radioactive isotopes? What other information is related to the question? Choose Answer Given what you now know, what information is most likely to produce the correct answer? Reflect on Process Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Which figure correctly illustrates the mechanism of action of the sodium-potassium pump?
A. A
B. B
C. C
D. D
The relationship between the concentration of a gas in solution and the partial pressure of that gas can be described by
A) Fick's law. B) Poiseuille's law. C) Dalton's law. D) Boyle's law. E) Henry's law.
Lysosomes
What will be an ideal response?