Blue text shows extra clarification or guidance.Guiding questionsSL and HLC4.2.1 - Ecosystems are open systems in which both energy and matter can enter and exitAs a contrast - in closed systems only energy is able to pass in and out (E.g. Sealed bottles containing plant communities.)C4.2.2 - Sunlight is the principal source of energy that sustains most ecosystems.Exceptions include ecosystems in caves and deep ocean...