Two students give the number of vertebrae of an adult…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Two students give the number of vertebrae of an adult. Ravi says . Julia says . Both quote a textbook.
- Which count follows NCERT?
- How does Julia get ?
- How many vertebrae are there in the cervical, thoracic and lumbar regions together?
Need a reminder? The key ideaShow
The skeleton has bones. The axial skeleton has bones: the skull ( cranial and facial bones), the hyoid (), the ear ossicles (), the vertebral column ( units: cervical, thoracic, lumbar, sacral, coccygeal), the sternum () and pairs of ribs (). Ribs: pairs true, pairs false, pairs floating.
The worked solution
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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. Two counts, and .
Plan. Find how each book counts the fused parts.
Step 1. (a) Ravi follows NCERT. It counts the sacrum as one unit and the coccyx as one unit.
Step 2. (b) Julia counts the vertebrae that fuse. The sacrum is five fused vertebrae and the coccyx is four. So she has .
Step 3. (c) .
Answer: (a) follows NCERT. (b) She counts the fused sacral and coccygeal vertebrae separately. (c) .
Check. NCERT: . Julia: . Both are right for their own way of counting.
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