Given below are two statements: Assertion (A): A typical unfertilized, angiosperm embryo sac at maturity is 8 nucleate and 7-celled. Reason (R): The egg apparatus has 2 polar nuclei. In the light of the above statements, choose the correct answer: (NEET 2025)
Answer: (A) (a) A is true but R is false. Answer: A.
- A.(a) A is true but R is false✓
- B.(b) A is false but R is true
- C.(c) Both A and R are true and R is the correct explanation of A
- D.(d) Both A and R are true but R is not the correct explanation of A
Correct Answer
(A) (a) A is true but R is false
Solution & Explanation
Answer: A. The Assertion is correct: after the 8-nucleate stage, cell walls form so that six nuclei become cells and two remain as polar nuclei in the central cell, giving a mature embryo sac that is 8-nucleate but 7-celled. The Reason is false because the egg apparatus (at the micropylar end) is made of two synergids and one egg cell only; the two polar nuclei are housed in the large central cell, not the egg apparatus. Hence A is true but R is false. NCERT: Ch 1, p.11, lines 17-25 — "Three cells are grouped together at the micropylar end and constitute the egg apparatus. The egg apparatus, in turn, consists of two synergids and one egg cell... The large central cell, as mentioned earlier, has two polar nuclei. Thus, a typical angiosperm embryo sac, at maturity, though 8-nucleate is 7-celled."