Ultimately, respiration and fermentation are simply different ways to conclude sugar catabolism. following the energy-yielding reactions, respiring cells pass electrons to oxygen (or other external inorganic oxidant), while fermenting cells dump electrons back onto a partially oxidized organic molecule (such as pyruvate), which then exits the cell as a waste product. either way, the goal is to do which of the following?
a. fully oxidize nadh into co2 and h2o
b. recycle nadh back to nad+
c. generate as much nadh as possible (then synthesize more nad+ if necessary)
d. break down nadh into biosynthetic precursors
e. stimulate de novo production of nad+
recycle nadh back to nad+

B. recycle NADH back to NAD+

Explanation:

Both respiration and fermentation share a common pathway, that is glycolysis. The redox reactions of glycolysis use NAD+ as an electron acceptor and NADH is formed. To continue the process of respiration and fermentation, oxidation of NADH into NAD+ is required so that NAD+ can serve as an electron acceptor for glycolytic reactions.

Aerobic respiration oxidizes NADH into NAD+ by transferring its electrons to the terminal electron acceptor, the molecular oxygen. On the other hand, fermentation oxidizes NADH through the formation of lactic acid or ethanol from pyruvate.

the answer is 1. photosynthesis. glad to

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.