NEET 2000 · Class 12

Principles of Inheritance and Variation

Mongolian Idiocy due to trisomy in 21st chromosome is called (2000)

  1. (A)Down's syndrome
  2. (B)Turner's syndrome
  3. (C)Klinefelter's syndrome
  4. (D)Triple X syndrome

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 the MCQ's description of 'Mongolian Idiocy due to trisomy in 21st chromosome' and distinguishes it from the other syndromes mentioned.

We did this for 1,565 questions.

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.

Take the free 5-minute checkMore from this chapter

Question text is reproduced from the published NEET 2000 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.