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Moderate

Global $CO_2$ Fixation Patterns

APBIO-LYE2NE

Below is a graph tracking the monthly levels of atmospheric carbon dioxide at the Mauna Loa observatory in Hawaii from 1991 to 2007.

"Carbon Dioxide Information Analysis Center." A Search Tool for Scientific Data. N.p., n.d. Web. 10 Mar. 2016. http://mercury.ornl.gov/cdiacnew/send/query?term1=mauna%2Bloa&term1attribute=text&term6attribute=datasource&term6=cdiac&x=0&y=0#.

Which of the following provides the BEST explanation for the pattern shown in the graph?

A

Rates of carbon fixation by terrestrial photosynthesizers increase and decrease significantly with the summer and winter seasons.

B

Rates of carbon production by terrestrial heterotrophs increase and decrease significantly with the summer and winter seasons.

C

Global wind patterns act to circulate atmospheric gases in a way that periodically collects carbon dioxide in higher levels over land masses.

D

The sensor technology used at the observatory was developed 40 years ago and is faulty.