alleryStart learning →The nitrogen cycle is introduced with the observation that getting nitrogen into the living world is:
AEffortless
BImpossible
CInstantaneous
DDifficult
Answer & Solution
Correct answer: D. Difficult
1. Each biogeochemical cycle has its own bottleneck.
2. Carbon is the second most abundant element in living organisms.
3. The nitrogen cycle is introduced separately from the carbon cycle.
4. Getting nitrogen into the living world is difficult.
5. That difficulty is what makes nitrogen fixation so important.
_Source: OpenStax Biology 2e (CC BY 4.0), Ch 46 'Ecosystems', sections 46.1-46.3_
Keep practising Ecosystems
Browse all Ecosystems questions for AP Biology, or explore more Biology topics.
Related questions
Complete the energy flowTrue or false: ecosystemsMatch each ecosystem termOrder the grazing food chainStop on the right trophic levelCarbon is described as which most abundant element in living organisms?Gross and net primary productivity differ by the energy that producers spend on:After a limited number of trophic energy transfers, the energy remaining may not be enough