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NEETZoologyPrinciples of Inheritance and Variation

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): In grasshoppers, the total number of chromosomes in a male somatic cell is one less than that in a female somatic cell. Reason (R): Grasshoppers exhibit the XX-XO type of sex determination, where males are heterogametic and produce two types of sperms. In the light of the above statements, choose t

Options

  1. ABoth (A) and (R) are correct but (R) is not the correct explanation of (A)
  2. BBoth (A) and (R) are correct and (R) is the correct explanation of (A)
  3. C(A) is correct but (R) is not correct
  4. D(A) is not correct but (R) is correct

Correct answer

B. Both (A) and (R) are correct and (R) is the correct explanation of (A)

Step-by-step solution

Assertion (A) is correct: In grasshoppers, females have a pair of X chromosomes (XX) while males have only one X chromosome (XO). Thus, the male somatic cell has one chromosome less than the female somatic cell. Reason (R) is also correct: Grasshoppers follow the XX-XO mechanism of sex determination. Males are heterogametic because they produce two types of sperms: 50% of the sperms carry an X chromosome and the other 50% carry no sex chromosome (O). Reason (R) correctly explains Assertion (A) because it is this ex

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