🔬 Biology · Locomotion and Movement · NEET

Of the twelve pairs of ribs, the number of 'floating' pairs not joined to the sternum is:

Answer: Two pairs.

A Five pairs
B Seven pairs
C Two pairs
D Twelve pairs

Correct answer: C. Two pairs

Explanation: The last two pairs (11th and 12th) are floating ribs, attached only to the vertebrae and not to the sternum.

Structure of a sarcomere showing thick myosin filaments and thin actin filaments with the Z line, M line, A band, I band and H zone labelled

A sarcomere (Z line to Z line): during contraction the I band and H zone shorten as thin filaments slide over thick, while the A band stays the same length. Image: SlothMcCarty, CC BY-SA 3.0, via Wikimedia Commons.

Concept context

Types of movement, muscle contraction, skeletal system, joints, and disorders. Important for Class 11 and NEET.

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Of the twelve pairs of ribs, the number of 'floating' pairs not joined to the sternum is:

Concept context

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