Question

muscle contraction interactive and video
which of the following statements is true?
the triceps is an extensor and the biceps is a flexor.
the biceps is an extensor and the triceps is a flexor.
the biceps and triceps are both extensors.
the triceps and biceps are both flexors.
the triceps and biceps bend your knees.
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Explanation:

• Muscle function basics: Flexor muscles decrease the angle between two body parts (e.g., bending the elbow), and extensor muscles increase the angle (e.g., straightening the elbow).
• Biceps and triceps roles: The biceps brachii is a flexor of the elbow joint (when it contracts, it bends the elbow). The triceps brachii is an extensor of the elbow joint (when it contracts, it straightens the elbow).
• Elimination of other options:
• The statement “The biceps is an extensor and the triceps is a flexor” is wrong as it reverses their actual functions.
• “The biceps and triceps are both extensors” and “The triceps and biceps are both flexors” are incorrect because they have opposite (but complementary) functions at the elbow.
• “The triceps and biceps bend your knees” is wrong; these muscles act on the elbow joint, not the knee joint.

Answer:

The triceps is an extensor and the biceps is a flexor.