Answer:
direct observation
Explanation:
because if your constantly monitoring them you should see any abnormal signs
The part of muscle that he needs to train is the Slow-twitch muscle fibers.
<h3>What are Slow-twitch muscle fibres?</h3>
The Slow-twitch muscle fibers are the muscle fibres that are used to support long distance endurance journey such as the marathon race.
Therefore, the part of muscle that he needs to train is the Slow-twitch muscle fibers.
Learn more about muscle here:
brainly.com/question/13920046
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CO2 levels of the blood are elevated. CO2 is a acid