Which term refers to the percentage of energy ingested that is assimilated?
“Assimilation efficiency” for which term refers to the percentage of energy ingested that is assimilated. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Ecosystem processes are constrained by energy conservation and by the cycling of matter. Energy enters mainly through primary production, is lost as metabolic heat at every transfer, and therefore cannot be recycled in the way that carbon, nitrogen, phosphorus, or water can. The remaining alternatives—“Production efficiency”, “Trophic efficiency”
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 3