Our planet is broken down into four systems or spheres: the atmosphere, lithosphere, hydrosphere, and biosphere. These systems are all interconnected and help provide balance on Earth and within the planet's ecosystems. Readers of this informative series will learn about cycles associated with each system and each system's impact on the planet as a whole. Additionally, these books discuss how humans interact with each system and how their activities can impact these systems, both positively and negatively.
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