Answer: I believe the right answer is B) atmospheric nitrogen→bacteria→plants→animals. I'm pretty sure!
Sorry for answering a bit late, hope that helps! :-)
Chloroplasts - found only in plants and algae. they convert solar radiation energy to chemical energy usable for the cell's metabolism.
mitochondria - found in both plants and animals, they produce energy (in the form of ATP - chemical compound) by decomposing sugars and fats. they use up oxygen to do it.
I think A makes the most sense..
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