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...introduction to this album What is an ecosystem? How the definition of an ecosystem as "a living system of energy transfer" arose The energy cycle Understanding the role of the sun, carbon, and energy interactions between organisms in ecosystems Humans enter the equation How human activity affects the delicate energy balance in an ecosystem with often adverse consequences...

...introduction to this album. Introduction to Ely and Chartres Cathedral A brief history of these two stunning Cathedrals, looking at their architecture and engineering. Stone John Trapp looks at stone as a building material, especially it's use in building the Parthenon in Greece. The Arch Using models, Professor Francis Evans explains how arches stay standing. John Trapp...