Match each step in the nitrogen cycle to its description. bacteria convert ammonia
to nitrites and nitrates
bacteria break down waste
products and return nitrogen
to the soil
bacteria convert nitrates
into nitrogen gas
plants and animals take in
and use nitrogen compounds
bacteria convert atmospheric
nitrogen to ammonia
nitrification
nitrogen fixation
>
ammonification
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Assume that a student is given two different models of bacteria, with one model consisting of big bacteria and the other consisting of small bacteria. how can the student demonstate the theory of endosymbiosis using the models

Which of the following scenarios is an example of the bottleneck effect? answers a in south africa, much of the afrikaner population is descended from a small number of dutch colonists. in this population, this is an unusually high frequency of pseudoxanthoma elasticum (pxe), an elastic tissue disorder. b four white-tailed deer are introduced to a park in finland. thirty years after their introduction scientists compare the genes in the population and find that there is no variation. c during the industrial revolution, london's air became filled with soot. as a result, birds started eating more of the lighter moths because they were easier to spot than their darker counterparts. over time, the moth population changed so that there were more darker moths than lighter ones. d 10% of the population of american alligators in an area have the recessive trait albinism. a massive flood results in the death of 80% of the population. of the remaining population, 60% have the recessive trait of albinism.

Up to what percentage of the world's flora consisted of cycads during the triassic period? 100% 75% 50% 20%