There have been 5 major mass extinctions throughout geological time. What
conclusion can be made about carbon dioxide levels and mass extinctions?
A: Mass extinction led to changes in CO₂ levels.
B: A change in CO₂levels brings about temperature changes that lead to mass
extinctions.
C: There is not relationship between CO₂ levels and mass extinction.
D: Only when CO₂ levels drop and an ice ages begin do mass extinctions
occur.