Layer 2 would be most likely to have organisms that lived at the same time as the bird species
U·ni·cel·lu·laradjective
BIOLOGY(of protozoans, certain algae and spores, etc.) consisting of a single cell.(of an evolutionary or developmental stage) characterized by the formation or presence of a single cell or cells.
Hope this helps!
C6H12O6 + 6O2 - > 6CO2 + 6H20 + Energy
I believe it comes from the groups of dNTPs. ( hydrolysis of phosphate )