These 'ecosystems' refer to the web of interactions of plants and animals with each other and with their immediate physical and chemical environment: the flow of energy through food chains and the cycling of nutrients.
(These 'ecosystems; refer; to the web of interactions of plants and animals with each other and with their immediate physical and chemical environment)
These 'ecosystems
refer
to the web of interactions of plants and animals with each other and with their immediate physical and chemical environment