Absence of oxygen in earth, made the atmosphere reducing. But it later became oxidizing in nature due to the emergence of ________

Absence of oxygen in earth, made the atmosphere reducing. But it later

1.	Absence of oxygen in earth, made the atmosphere reducing. But it later became oxidizing in nature due to the emergence of ________
A.	Angiosperms
B.	Gymnosperms
C.	Eukaryotic algae
D.	Cyanobacteria
Answer» E.