The main differences in genetic make-up between archaea and eubacteria are gene sequences of rRNA
cell membrane properties
enzymes and metabolic pathways
all of the above

ability to bond woth oxygen

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.

bal is blood alcohol level. bac will normally be higher in a person with more body fat. so the answer to your question would be, as body fat decreases, the increasing rate of bal decreases.  

(nitrogen fixation) will be your answer sorry if im wrong