The answer is D. Always true in all places
<span>The nitrogen cycle could not exist without first nitrogen. The cycle is about this specific element which goes to show that if this element is not present then, there will not be any nitrogen cycle. Also, an important factor for the cycle is the presence of the bacteria and other microorganism which are needed for the fixation. </span>
I believe the answer is "biodegradable". Hope this helps!
