Final answer:
A carbon atom's journey starts in a red giant star and travels to Earth, where it circulates between plants, animals, humans, and the atmosphere, demonstrating the ubiquitous cycle of carbon in nature.
Step-by-step explanation:
Once upon a time in the cosmos, a carbon atom embarked on an extraordinary journey. Born in the fiery belly of a red giant star, this tiny particle was a product of the triple-alpha process, where it fused from helium nuclei. When the star ended its life cycle, the carbon atom was flung into space, eventually making its way to Earth, the third rock from the Sun. On our planet, it found a home within a plant, entering through photosynthesis and becoming part of the plant's structure. When a grazing animal consumed the plant, the carbon atom became part of its tissue. Afterward, a predator consumed the grazing animal, and the carbon atom found its way into a new organism.
For a brief moment in time, the carbon atom became part of a human being, peacefully residing within the tissues, participating effortlessly in the symphony of life. Ultimately, as all matter does, it was released back into the Earth's atmosphere as CO₂ through respiration, completing this part of its journey. Each stop, from the stardust to the dynamic Earth life forms, illustrates the critical role of carbon in life and the versatile nature of its bonding, which underpins the diversity of organic molecules like methane (CH₄).