The Energetics of Photosynthesis Often Overshadows the Importance of Carbon

Multiple Choice

The energetics of photosynthesis often overshadows the importance of carbon fixation, but without this vital process,

A) carbon dioxide levels would rise uncontrollably, making the Earth too warm to support life.
B) atmospheric oxygen levels would be too low to support life on Earth.
C) carbon atoms would not be readily available in biologically useful forms, causing organisms to grow and reproduce very slowly.
D) all of the above