A: Eight cells of octant stage in dicot embryogeny are made by 2 vertical and one tranverse divisions in embryonal cell
R: These cells are arranged in epibasal and hypobasal tier

Options

A. if both assetion A reason are ture and the reason is the correct explanation of the assertion then mark
B. if both assertion & reason are ture and the reason is not the correct explanation of the assertin then mark
C. if assertion is true statement but reason is false then mark
D. if both assertion and reason are flase statements then mark

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided in the context of dicot embryogeny.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Eight cells of octant stage in dicot embryogeny are made by 2 vertical and 1 transverse divisions in embryonal cell."
- In dicot embryogeny, the zygote undergoes several mitotic divisions. Initially, the zygote divides to form two cells: a terminal cell (towards the chalaza) and a basal cell (towards the micropyle).
- The terminal cell further divides to contribute to the pro-embryo, while the basal cell divides to form the suspensor.

2. **Analyzing the Division**:
- The formation of the octant stage involves multiple divisions. Specifically, the assertion mentions 2 vertical and 1 transverse division.
- However, the correct sequence of divisions leading to the octant stage actually involves more than just these three divisions. The assertion is incorrect because it does not accurately describe the total number of divisions that occur.

3. **Understanding the Reason (R)**:
- The reason states that "These cells are arranged in epibasal and hypobasal tier."
- In the octant stage, the eight cells are indeed arranged in two tiers: the epibasal tier (upper tier) and the hypobasal tier (lower tier).
- This arrangement is crucial for the future development of the embryo, where the hypobasal cells will contribute to the hypocotyl and the epibasal cells will contribute to the epicotyl.

4. **Conclusion**:
- The assertion is false because it inaccurately describes the number of divisions leading to the octant stage.
- The reason is true as it correctly describes the arrangement of the cells.
- Therefore, the correct answer is that both the assertion and reason are true, but the reason is not the correct explanation of the assertion.

### Final Answer:
B: Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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