Which of the following elements is released into the atmosphere by all of these processes:
1. volcanic outgassing
2. animal respiration and flatulence
3. burning of fossil fuels
4. metamorphism of limestone

Carbon

Explanation:Carbon is the element released by volcanic outgassing,animal respiration and flatulence,burning of fossil fuels and the metamorphism of limestone.

Volcanic outgassing is the release of carbon into the atmosphere mainly in the form of carbon monoxide.

Animal respiration and flatulence are process taking place in animals which leads to the release of carbon dioxide.

Burning of fossil fuels is the use of heat to breakdown fossil fuels such as petroleum leading to the release of Carbon.

Limestone metamorphism is the breakdown of limestone which leads to the release of Carbon to the atmosphere.