Which class of biological polymer has the greatest functional diversity (can do the most jobs in a cell)?

PROTEIN

Explanation:

Proteins are the most diverse biomolecules on Earth, performing many functions required for life. Protein enzymes are biological catalysts, maintaining life by regulating where and when cellular reactions occur. Structural proteins provide internal and external support to protect and maintain cell shape.

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.