Final answer:
The incorrect statement regarding muscle contraction is that calcium ions trigger the release of neurotransmitters; instead, they bind to troponin to facilitate the contraction process.
Step-by-step explanation:
The statement that does not accurately describe muscle contraction is: b) Calcium ions trigger the release of neurotransmitters. This is incorrect because the neurotransmitter acetylcholine (ACh) is released by a motor neuron to initiate muscle contraction. Instead, calcium ions play a critical role in muscle contraction by binding to troponin, which in turn causes tropomyosin to shift and expose binding sites on actin filaments for the myosin heads. The myosin heads then bind to actin filaments (statement a), and this action requires the hydrolysis of ATP. Finally, ATP is indeed required for muscle relaxation because it is necessary for the detachment of myosin heads from the actin (statement c), and during contraction, the sarcomeres do indeed shorten as the filaments slide past each other (statement d).