Out of ‘X’ pairs of ribs in humans only 'Y' pairs are true ribs. Select the option that correctly represents values of X and Y and provides their explanation:
X=12, Y=5 True ribs are attached to vertebral column and sternum on the two ends.
X=24, Y=7 True ribs are dorsally attached to vertebral column but are free on ventral side.
X=24, Y=12 True ribs are dorsally attached to vertebral column but are free on ventral side.
X=12, Y=7 True ribs are attached dorsally to vertebral column and ventrally to the sternum.
According to the NCERT text, there are 12 pairs of ribs in humans (X=12). The first seven pairs are called true ribs (Y=7). These true ribs are attached dorsally to the thoracic vertebrae and ventrally connected to the sternum with the help of hyaline cartilage. The 8th, 9th, and 10th pairs are vertebrochondral (false) ribs, and the 11th and 12th pairs are floating ribs.
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