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Q.
To make chromosomal studies easier, chromosomes
are classified into certain groups. So, the chromosome
number $21,22 $ and $Y$ are listed in
Molecular Basis of Inheritance
Solution:
Chromosome number $21, 22$ and $Y$ are listed in $G$ group.
To make chromosomal studies easier, chromosomes are classified into Groups $A$ to $G$ as given below.
Group $A$ contains $1-3$ chromosomes
$B$ contains $4-5$ chromosomes
$C$ contains $6-12$ chromosomes and $X$-chromosome
$D$ contains $13-15$ chromosomes
$E$ contains $16-18$ chromosomes
$F$ contains $19-20$ chromosomes
$G$ contains $21-22$ chromosomes and $Y$- chromosome