The carbon cycle is the process by which carbon atoms are recycled through the Earth's ecosystems, atmosphere, and geology. It involves several key processes, including photosynthesis, respiration, decomposition, and combustion. Carbon is absorbed by plants from the atmosphere and converted into organic matter, which is then consumed by animals. When organisms die or respire, carbon returns to the atmosphere, contributing to the greenhouse effect. Understanding the carbon cycle is essential for addressing issues like climate change and ecosystem health.