Answer:
c. is a biotic factor within an ecosystem
1. Oxidized
2. Reduced
3. Glucose
4. Pyruvate
5. NAD+
6. NADH
An acronym for understanding gain and loss of electrons is OIL RIG (Oxidation is Loss of electrons, Reduction is Gain of electrons).
4. Gene frequencies will remain constant
The right answer is C
This process is called anaerobic respiration. It doesn't need dioxygen to occur (it can happen with or without O2).
Anaerobic respiration is a mechanism in which electrons pass through a chain of transporters whose final acceptor is a mineral substance other than oxygen, unlike aerobic respiration where the final acceptor is dioxygen. The final acceptor may be the nitrate ion (as in the case of Pseudomonas), carbon dioxyde or the sulfate ion.
Some bacteria (Pseudomonas) are able, anaerobically, to reduce nitrates to nitrites and then, depending on the case, to dinitrogen (with the enzyme Nitrate reductase A).
NO3- ==> NO2- ==> N2.
