Answer AND Explanation:
Darwin describes natural selection as a process whereby nature selects those organisms that have favourable characteristics to be parents of the next generation. The individuals possessing the favourable traits are better suited to the prevailing environmental conditions. This enables them to stand a better chance to survive in the struggle for existence due to limited resources.
I think its C. global warming
because the other one directly threats aquatic bio diversity while global warming doesn't just affect aquatic biodiversity
Answer:
dear user nitrogen fixation is so important bcoz of the reasons given above