How do biotic (living) and abiotic (non-living) things interact in an ecosystem? What are the relationships between and among abiotic (non-living) and biotic (living) factors in an ecosystem? How does energy flow within ecosystems? What are renewable and non-renewable energy sources, and why are they important? What is the difference between potential and kinetic energy? Why is the water cycle important? How can human activities affect the water cycle? in a parigraph