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

Options

A. X = 12, Y = 7 Ture ribs are attached dorsally to vertebral column and ventrally to the sternum.
B. X = 12, Y = 5 True ribs are attached dorsally to vertebral column and sternum on the two ends.
C. X - 24, Y = 7 Ture ribs are dorsally attached to vertebral column but are free on ventral side.
D. X = 24, Y = 2 True ribs are dorsally attached to vertebral column but are free on ventral side

Answer

To solve the question regarding the number of rib pairs in humans and how many of those are true ribs, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Total Pairs of Ribs (X)**:
- Humans have a total of 12 pairs of ribs.
- Since each pair consists of 2 ribs, this results in a total of 24 ribs.
- Therefore, X = 12.

2. **Identify True Ribs (Y)**:
- True ribs are defined as those ribs that are directly attached to the sternum (the breastbone) at the front.
- In humans, the first 7 pairs of ribs (from the 1st to the 7th pair) are classified as true ribs because they connect directly to the sternum.
- Therefore, Y = 7.

3. **Conclusion**:
- The values of X and Y are X = 12 and Y = 7.
- This means there are 12 pairs of ribs in total, out of which 7 pairs are true ribs.

### Final Answer:
- X = 12, Y = 7 (True ribs are attached dorsally to the vertebral column and ventrally to the sternum).

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