Identify the following description if it is a factor that contributes to muscle fatigue, muscle endurance or neither:
a. density of blood capillaries -
b. depletion of acetylcholine -
c. uncontrolled leakage of calcium from the sr -
d. depletion of atp -
e. a muscle's supply of glycogen -
f. a muscle's supply of myoglobin -
g. accumulation of potassium in the extracellular fluid -
h. the size of the motor unit a muscle belongs to -