The graph shows atmospheric carbon dioxide levels over time, Atmospheric CO, Levels
(Mauna Loa Observatory)
Monthly values
Normalized values
Parts per million
380
360
340
320
1960 1970 1950 1990 2000 2010
Year
Graph and data copyright Scription of Oceanography,
NOAA Earth System Research Laboratory, December 2016
Which two observations are most useful for explaining the trends in the data? Select two answer choices
Photosynthesis and cellular respiration have opposite effects on carbon dioxide levels
Carbon is stored in solid form in shells rocks and sediments
Atmospheric carbon dioxide may dissolve in ocean water,
The burning of fossil fuels adics carbon dioxide to the atmosphere.
Activities that produce or take up carbon dioxide vary with the seasons