Why can't astronomers measure the parallax of a star that is a million light years away?

One of the methods used widely to calculate the distance of nearby or closer objects in astronomy is Parallax. The distance of the stars are usually expressed in light years but the unit of distance is parsec or parallax second.  

                                        1 Parsec = 3.26 light years

Astronomers are not able to measure the parallax of a star that is a million light years away because the star is too far and the distance with which the start appears to move is too less to be calculated accurately.

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.