Earlier in history, the earth's atmosphere was most likely not friendly to organisms that needed oxygen to breathe. Today, however, the earth's atmosphere contains the oxygen needed for eukaryotic organisms. The oxygen was produced by cyanobacteria through the process of . volcanism
photosynthesis
metabolism
respiration

If we review the changes in the landscape surrounding the great salt lake in utah we can see a change in topography. look at the area to the south of the lake. what change has occurred during the last twenty-nine years? a) erosion of the hills b) an increase in marshland c) flooding of the area and the development of wetlands d) deposition of sediments and an increase in elevation