Energy flow: productivity, intake, assimilation, feces, etc

What are the mistakes in here?

I: Intake
F: Feces
A: Assimilation (Assimilation=Intake-Feces)
R: Respiration
P: Production (Production=Assimmilation-Respiration and Production = Intake - Feces - Respiration)


A certain animal has a production efficiency (P/A) of 2%, while his assimilation efficiency is 80%.

1. Calculate the productivity P in KJ if this animal has an energy content of 100 KJ.

I guess you have to multiply the production efficiency with the assimilation efficiency and the energy content: 0.80*0.02*100=1.5 KJ

2. What amount of energy of this animal will benefit a higher trophic level?

I think this is the feces (=Intake-Assimilation) = 20 KJ.

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It won't be feces. It would be productivity. –  biogirl Nov 6 '13 at 9:20
Can you clarify what "energy content.."of the animal means? Part 2 is wrong, since it is the productivity(P) that will benefit a higher trophic level.(faeces benefits decomposers which are usually not addressed as "higher" trophic level) –  Satwik Pasani Nov 7 '13 at 10:29