The correct answer is: A. carbon dioxide cycle.
The carbon dioxide cycle is a biogeochemical cycle that involves the exchange of carbon between the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to making Earth capable of sustaining life.
The carbon cycle begins with the Earth’s atmosphere, which contains about 78% nitrogen, 21% oxygen, and 1% other gases, including carbon dioxide. Plants take in carbon dioxide from the atmosphere through photosynthesis and use it to create organic compounds, such as carbohydrates, lipids, and proteins. Animals eat plants or other animals that have eaten plants, and they use the carbon in these organic compounds to build their own bodies. When plants and animals die, their bodies decompose and release carbon dioxide back into the atmosphere.
The carbon cycle also includes the Earth’s oceans, which contain about 50 times more carbon than the atmosphere. Carbon dioxide dissolves in seawater and is used by marine plants and algae to create organic compounds. When these organisms die, their bodies sink to the bottom of the ocean and are buried in sediments. Over time, these sediments are converted into fossil fuels, such as coal, oil, and natural gas.
Human activities are also affecting the carbon cycle. When we burn fossil fuels, we release carbon dioxide into the atmosphere. This is causing the Earth’s atmosphere to warm, which is leading to climate change. We are also clearing forests, which removes plants that take in carbon dioxide from the atmosphere. This is also contributing to climate change.
The carbon cycle is a complex system that is essential for life on Earth. It is important to understand how the carbon cycle works so that we can protect it from human activities.
The other options are not examples of one-way ecological cycles. The water cycle is a closed system, meaning that the water on Earth is constantly recycled. The energy cycle is also a closed system, meaning that energy is constantly being transferred from one form to another. The oxygen cycle is a open system, meaning that oxygen is constantly being exchanged between the Earth’s atmosphere and the biosphere.