[ 473 ] Physical Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1940 1950 1960 1970 1980 1990 2000 2010 Year 400 375 350 325 300 275 CO 2 8.38 8.33 8.28 8.23 8.18 8.13 8.08 8.03 pH Atmospheric CO 2 (ppmv) Seawater pCO 2 (µatm) Seawater pH What are the items that are correlated in this graph in your own words?