The answer is B. Uneven rock layer.
Uneven rock layer can directly lead to nonconformity on an exposed rock. Usually the rocks are layered evenly. When the rocks are uneven it will be exposed and show different kind of rocks.
~Hello there! ^_^
Your question: How often is CO2 cycled through the atmosphere?
Your answer: CO2 is cycled through the atmosphere in 350 years.
Hope this helps~