Which of the following is a correct match?

(A)Down's syndrome - 21st chromosome
(B)Sickle cell anaemia - X-chromosome
(C)Haemophilia - Y-chromosome
(D)Parkinson's disease - X and Y chromosome

The NCERT line that answers it

Verbatim line

Down's syndrome results in the gain of extra copy of chromosome 21.

Chapter: Principles of Inheritance and Variation
Section: 4.8.3 Chromosomal Disorders

The answer appears as a continuous sentence in NCERT. This is that sentence.

How this line gives the answer

0, emb=1.0, combined=1.0). Verified: high — The span explicitly states 'Down's syndrome results in the gain of extra copy of chromosome 21', which directly matches option A and distinguishes it from the incorrect options.

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Every one traced to the exact sentence in NCERT that answers it, including 90% of the 2026 paper. Sit a mock on the real NEET 2027 computer interface and every mark you drop comes back with its line attached.

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Question text is reproduced from the published NEET 2002 paper for study and commentary. NCERT text is quoted, not redistributed; textbooks remain at ncert.nic.in. Our mapping method, including its measured error rates, is published at /methodology.