Question

Assertion : Down’s syndrome is caused due to absence of either X or Y sex
chromosome 1
Reason : Such individuals show mental retardation and broad head with
characteristic features
(a) Assertion and reason both are correct statements and reason is correct
explanation for assertion.
(b) Assertion and reason both are correct statements but reason is not correct
explanation for assertion.
(c) Assertion is correct statement but reason is wrong statement
(d) Assertion is wrong statement but reason is correct statement

Answer 1

Answer:

D

Explanation:

downs syndrome is an autosomal disease. no sex chromosome are involved in it

Answer 2

(d) Assertion is wrong statement but reason is correct statement

• Down's Syndrome is a kind of a Chromosomal disorder or genetic disorder in which an additional copy of chromosome number 21 takes place. This is also called as the triosomy of chromosome 21.
• Since the disease happens by increment in chromosome number and not by absence of X or Y sex chromosome 1 hence, the given assertion is incorrect.
• This disorder is accompanied by features like broad flat face, palm crease, mental retardation. Hence, the given reason is correct.