Question

volcanic activity also releases carbon stored below earths surface into the atmosphere. when they erupt, volcanoes release lava, ash, and gases, including co₂. over earths history, volcanic activity has emitted a large amount of co₂ into the atmosphere. however, the amount of co₂ emitted by volcanoes each year is small compared to the amount emitted by fossil fuel combustion. for example, the 1980 eruption of mount saint helens in washington state released 10 million tons of co₂ into the atmosphere over 9 hours. by comparison, human activities emit that same amount of co₂ in just 2.5 hours. the 1980 eruption of mount saint helens sort the processes based on whether they store or release carbon. fossil fuel formation fossil fuel combustion volcanic activity limestone formation

Explanation:

Fossil fuel formation traps carbon over time as organic matter is compressed and transformed into fossil fuels. Limestone formation involves the incorporation of carbon - containing compounds into sedimentary rocks, storing carbon. Fossil fuel combustion releases the stored carbon in the form of carbon - dioxide when burned. Volcanic activity releases carbon stored below the Earth's surface into the atmosphere as part of eruptions.

Answer:

Store carbon: fossil fuel formation, limestone formation
Release carbon: fossil fuel combustion, volcanic activity