The T tubules store Ca2 . provide a means of rapidly transmitting the action potential from the surface into the central portions of the muscle fiber. store ATP. run longitudinally between the myofibrils. have expanded lateral sacs.

provide a means of rapidly transmitting the action potential from the surface into the central portions of the muscle fiber

Explanation:

T-tubules or Transverse tubules are the tube-like structures present in the muscle fibers.

The T tubules are formed by the modification in the plasma membrane of the cell and therefore arise from the surface of the muscle cell.  The T tubules then pass through the muscle and enter the inner core of the muscle that is near to the sarcoplasmic reticulum.

The main function of the T tubules is to carry forward the action potential from the synaptic junction to the muscle where it triggers the release of the calcium from the muscle.

Thus, the selected option is correct.

a and b

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.