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Principles Of Inheritance And Variation

Question
CBSEENBI12047038

Assertion : In humans, the gamete contributed by the male determines whether the child produced will be male or female.

Reason : Sex in humans is a polygenic trait depending upon a cumulative effect of some genes on X chromosome and some on Y-chromosome.

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false

Solution

C.

If Assertion is true but Reason is false

In humans, sex is determined by sex chromosomes. females consists of XX pair of sex chromosome and males consists of XY pair of sex chromosomes. Therefore, males determine the sex of the offspring. Sex in humans is monogenic trait.

Human skin, hair and eye colour are polygenic traits as they are influenced by more than one allele at different loci. the result is the perception of continuous gradation in the expression of these traits.