The genetic defect-adenosine deaminase (ADA) deficiency may be cured permanently by

(A)administering adenosine deaminase activators
(B)introducing bone marrow cells producing ADA into cells at early embryonic stages
(C)enzyme replacement therapy
(D)periodic infusion of genetically engineered lymphocytes having functional ADA cDNA

The NCERT line that answers it

Verbatim line

However, if the gene isolate from marrow cells producing ADA is introduced into cells at early embryonic stages, it could be a permanent cure.

Chapter: Biotechnology and its Applications
Section: 10.2.2 Gene Therapy
Page: 5
Words matched: 24 of 24

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 that introducing the gene from marrow cells producing ADA into cells at early embryonic stages could be a permanent cure, which directly matches and justifies option B.

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Question text is reproduced from the published NEET 2009 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.