How does a single undifferentiated cell lead to a complex multicellular organism?

The answer is the cell becomes specialized in function and form through differentiation.  The process that leads a single undifferentiated egg cell to develop into a complex organism is not fully understood. This process of differentiation is an area of active research. It is known that the key lies in methods of gene expression.              

the aswer is letter c

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.