Down’s syndrome in humans is due to

Options

(a) Two ‘Y’ chromosomes
(b) Three ‘X’ chromosomes
(c) Three copies of chromosomes 21
(d) Monosomy

Correct Answer:

Three copies of chromosomes 21

Explanation:

Down’s syndrome is the chromosomal disorders due to the presence of an additional copy of the chromosome. Number 21 (trisomy of 21). The affected individual is short saturated with small round head, furrowed tongue and partially open mouth and mental development is retarted.