Purple and green sulfur bacteria use ___________________ as the electron donor to reduce carbon dioxide.

Purple and green sulfur bacteria use ___________________ as the electr

1.	Purple and green sulfur bacteria use ___________________ as the electron donor to reduce carbon dioxide.
A.	S<sup>2-</sup>
B.	SO4<sup>2-</sup>
C.	H<sup>2</sup>S
D.	Organic acids
Answer» D. Organic acids