Q1. [1] § 7.3.3 (b) Female Reproductive System
Assertion (A) : The embryo gets nutrition from the mother's blood with the help of a special tissue called placenta.
Reason (R) : Placenta is a disc which is embedded in the uterine wall.
- A Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- B Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
- C Assertion (A) is true, but Reason (R) is false.
- D Assertion (A) is false, but Reason (R) is true.
Previously asked in CBSE board exam
2025 31/5/1 Q18
Generated by claude-sonnet-4-6 · 2026-06-15 06:44 · grounding rag
Model Answer
Option (B): Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
The Assertion is correct. The Reason is also true — placenta is indeed a disc embedded in the uterine wall — but it merely describes the structure of the placenta, not how it provides nutrition to the embryo.
Explanation
- The A is directly from the textbook: "The embryo gets nutrition from the mother's blood with the help of a special tissue called placenta."
- The R is also textbook-accurate: "This is a disc which is embedded in the uterine wall."
- However, R explains the location/structure of the placenta, not the mechanism of nutrition transfer (villi, blood spaces, large surface area). So R does not explain A — hence option (B).
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