Final answer:
The correct answer to the question is 'a. Nerve; Artery,' as each skeletal muscle fiber receives signals to contract from a somatic motor neuron and is supplied with nutrients and oxygen by an artery, with waste removal by a vein.
Step-by-step explanation:
Your muscles are indeed energy-intensive systems within your body. Each muscle fiber in a skeletal muscle is supplied by the axon branch of a somatic motor neuron, which signals the fiber to contract. Alongside this neural support, every muscle is also richly supplied by blood vessels, with each muscle having its own artery for nutrient and oxygen delivery and its own vein for waste removal. Therefore, the correct answer to the question is: a. Nerve; Artery.