The number of cervical vertebrae in a human body is:

Question

UnlockIAS · Accepted Answer

Correct — B, 7. The human vertebral column has 7 cervical vertebrae (C1–C7) in the neck region — a fixed count found in almost all mammals, including the giraffe (whose cervical vertebrae are simply far longer, not more numerous). C1 (the atlas) supports the skull, and C2 (the axis) allows the head to rotate.

Why the other options are wrong — (a) Too few — no mammalian cervical region, including the human one, normally has just 5 vertebrae; a handful of sloth species are the rare exception.  (c) 12 is the number of THORACIC vertebrae (one pair of ribs attaches to each) — a different region of the spine, not the cervical one.  (d) 23 is unrelated to the vertebral column; it is the well-known number of chromosome PAIRS in a human body cell (46 chromosomes total) — a different topic (genetics) entirely, planted here as a trap.

Concept: The human vertebral column (spine) has 33 vertebrae grouped into five regions: 7 cervical (neck), 12 thoracic (upper back, one pair of ribs each), 5 lumbar (lower back), 5 sacral (fused into the sacrum), and 4 coccygeal (fused into the coccyx/tailbone). Only the top 24 (7 + 12 + 5) remain separate, moveable vertebrae in an adult; the sacral and coccygeal ones fuse, so the commonly cited 'moveable spine' count is 26.

State PCS 2024 Q6 — Science & Technology PYQ with Answer

State PCS 2024 Q6 — Science & Technology PYQ with Answer