The Gaia theory proposes that the Earth functions as a self-regulating system, where living organisms interact with their environment to maintain conditions suitable for life. This idea, introduced by scientist James Lovelock, suggests that the biosphere, atmosphere, oceans, and soil work together to create a stable climate and promote the survival of various species. According to the Gaia theory, even small changes in one part of the system can affect the whole. For example, plants produce oxygen, which is essential for animals, while animals produce carbon dioxide, which plants need. This interconnectedness highlights the importance of preserving our planet's ecosystems.