About a billion years ago, the first complex cell is thought to have evolved by the fusion of two
cells. This is the Endosymbiotic Theory and two organelles found in eukaryotes to support this
theory of evolution are chloroplasts and mitochondria. What was thought to be the host cell?
a. Nucleus
b. Cell membrane
C. Protista
d. Archaea bacterium.

ecological efficiency: % of usable energy transferred as

biomass from one trophic level to the next typical is 10% efficient (90% of

energy is lost),is diagramed as the pyramid of energy flow. then osprey eagle

are tertiary consumer and the shrimp are primary consumer, so to balance

mass of shrimp (1/0.1) / 0.1 = 100 kg 

the correct answer is d

c should be the answer

only about ten percent of the energy at one trophic level is passed on to organisms at the next trophic level. the remainder of the energy is used in life processes or lost as heat.