PDF chapter test TRY NOW

Complete the following cycle given as figure by filling the boxes (a), (b), (c), (d).
 
YCIND_231103_5708_CBSE _8th_5.png
 
a.
b.
c.
d.
Answer variants:
Light fixes nitrogen.
N-waste from excretion and death.
Bacteria and blue-green algae fix atmospheric nitrogen.
Bacteria convert nitrogen compounds into gas.