You are studying an outcrop where the base layer is limestone and the layer directly on top of that is sandstone. Near the base of the sandstone are small, weathered pieces of limestone entirely contained within the sandstone
Explain how these pieces of limestone came to be contained within the sandstone.
What will be an ideal response?
Answer: The limestone was exposed at the surface for a long time, which weathered the surface of the limestone to create larger pieces of it. When the sandstone was deposited, these pieces were included among the sands.
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Using this plot of annual peak discharge, what is the probability each year that a flood of 1,000 cubic meters per second will occur?
A) 1 in 1,000, or 0.01%
B) 1 in 100, or 1% (100-year flood)
C) Between 10% and 20%
D) More than 20%
Surface high pressure zones are usually associated with:
A) stormy weather. B) converging winds. C) clear or nearly clear weather. D) ascending air.
Inner city population densities were generally ________, speaking to the quality of life in inner cities
A) comparable to suburban densities B) equal to that found in rural areas C) comparable to population density of the United States as a whole D) significantly higher E) impossible to measure because no census statistics were collected for inner cities
How have scientists used isotopic analysis to determine that the rise of atmospheric CO2 is mostly from the burning of fossil fuels?
A) 14C concentrations are much higher in urban areas than in rural areas, indicating fossil fuels must have a higher 14C/12C ratio than carbon from other sources. B) Since 14C is an unstable isotope, scientists have dated the atmospheric carbon to the period since the Industrial Revolution. C) Both coal and oil contain a high proportion of 14C. By analyzing 14C/12C ratios, scientists have been able to determine the source based on this fact. D) The decrease in ratios of atmospheric 13C and 14C to 12C indicates that the source is fossil fuel carbon.