Atmospheric Carbon Dioxide Levels Are Increasing Because

Multiple Choice

Atmospheric carbon dioxide levels are increasing because

A) human agriculture has greatly increased the amount of carbon dioxide given off by plants during respiration.
B) human activities have begun to release carbon that was formerly sequestered in fossil fuels into the atmosphere.
C) holes in the ozone layer have reduced the total amount of photosynthesis occurring in the biosphere.
D) the huge growth of the human population and the domestic livestock population has increased the amount of carbon dioxide being released through respiration.