Coal, limestone, petroleum, animal shells are all related to:

The correct answer is Carbon Cycle.

Key Points

• The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere.
• Since our planet and its atmosphere form a closed environment, the amount of carbon in this system does not change. Where the carbon is located in the atmosphere.
• On Earth, most carbon is stored in rocks and sediments, while the rest is located in the ocean, atmosphere, and in living organisms. These are the reservoirs, or sinks, through which carbon cycles.
• Carbon is released back into the atmosphere when organisms die, volcanoes erupt, fires blaze, fossil fuels are burned, and through a variety of other mechanisms.
• Thus, coal, limestone, petroleum, and animal shells are all result of the Carbon Cycle. Hence, Option 4 is the correct answer.