The muscle weakness of myasthenia gravis results from
a) insufficient acetylcholine release from presynaptic vesicles.
b) the motor neuron action potential being too small to shock the muscle fibers.
c) loss of acetylcholine receptors in the end-plate membrane.
d) excessive acetylcholinesterase that destroys the neurotransmitter.
e) All of the above probably contribute to the weakness.
Answer: C