A.
Commuters drive personal vehicles to their places of work: offices, manufacturing plants etc.
Some may use car pooling or mass transit like buses. But too many want the luxury and convenience of coming and going on their own terms.
IMHO car pooling and mass transit needs to be used more to reduce environmental harm.
On my work the answer was D ..
A Muscle Contraction Is Triggered When an Action Potential Travels Along the Nerves to the Muscles. Muscle contraction begins when the nervous system generates a signal. The signal, an impulse called an action potential, travels through a type of nerve cell called a motor neuron.
They can also use carbohydrates so I don't know