Match Column 1 with Column 2: Column 1 Column 2 (a) Down's Syndrome (…

The correct answer is Option (1) → a-ii; b-iv; c-iii; d-i

(a) Down’s Syndrome — this matches (ii) Trisomy 21. It is caused by an additional copy of chromosome 21, so the person has three copies of it.

(b) Turner’s Syndrome — this matches (iv) 45 with XO. One X chromosome is absent, so the female has 45 chromosomes with X0. Such females are sterile.

(c) Klinefelter’s Syndrome — this matches (iii) Karyotype of 47, XXY. An extra X chromosome in a male gives 47 chromosomes with XXY.

(d) Thalassemia — this matches (i) Mendelian Disease. It is an autosome-linked recessive blood disease. A mutation or deletion reduces the synthesis of one of the globin chains of haemoglobin. The other three are chromosomal disorders.

NCERT Extract:
Mendelian Disorders – “… Most common and prevalent Mendelian disorders are Haemophilia, Cystic fibrosis, Sickle-cell anaemia, Colour blindness, Phenylketonuria, Thalassemia, etc.”
Chromosomal Disorders – “… Down’s Syndrome : The cause of this genetic disorder is the presence of an additional copy of the chromosome number 21 (trisomy of 21). … Klinefelter’s Syndrome : This genetic disorder is also caused due to the presence of an additional copy of X-chromosome resulting into a karyotype of 47, XXY. … Turner’s Syndrome : Such a disorder is caused due to the absence of one of the X chromosomes, i.e., 45 with X0, Such females are sterile as ovaries are rudimentary besides other features including lack of other secondary sexual characters (Figure 4.17 b).”