What happens to the muscle fibres (muscle cells) as the arm flexes and
exterds?

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Explanation:

When a muscle contracts, the fibers shorten it to an even larger lump. For example, extend and then flex your biceps brachii muscle; the large, middle section is the stomach.

start studying ch. 18: body composition and nutrition for health. learn vocabulary, terms, and more with flashcards, games, and other study tools. what is a factor to less severe obesity? represents 60-75% total energy expenditure

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