How Do Scientists Estimate the Atmospheric Levels of Carbon Dioxide

question 45

Multiple Choice

How do scientists estimate the atmospheric levels of carbon dioxide that existed on Earth hundreds or thousands of years ago?

• A) They deduce it from the carbon dioxide content of fossil fuels.
• B) They measure it from bubbles of gas trapped in Antarctic ice.
• C) They estimate it from the relative numbers of carbon-based life forms that existed over time.
• D) They measure it from erupting volcanoes, bubbling hot springs, and seeping hydrothermal vents.

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Definitions:

Volume Variance

A financial metric that measures the difference between the expected sales volume and the actual sales volume.

Spending Variance

The difference between the budgeted or standard cost of something and its actual cost, which can indicate areas of inefficiency or savings.