Which one of the following can be explained on the basis of Mendel's law of Dominance? A. Out of one pair of factors one is dominant and the other is recessive. B. Alleles do not show any expression and both the character appear as such in F2 generation. C. Factors occur in pairs in normal diploid plants. D. The discrete unit controlling a particular character is called factor. E. The expression of only one of the parental characters is found in a monohybrid cross. Choose the correct answer from the options given below:
Answer: (A) A, C, D and E only. Answer: (A) A, C, D and E only Solution: The Law of Dominance states that characters are controlled by discrete units called factors which occur in pairs, and in a dissimilar pair one factor dominates the other; it explains the expression of only one parental character in a monohybrid F1 (statements A, C, D, E).
- A.A, C, D and E only✓
- B.B, C, and D only
- C.A, B, C, D and E
- D.A, B and C only
Correct Answer
(A) A, C, D and E only
Solution & Explanation
Answer: (A) A, C, D and E only Solution: The Law of Dominance states that characters are controlled by discrete units called factors which occur in pairs, and in a dissimilar pair one factor dominates the other; it explains the expression of only one parental character in a monohybrid F1 (statements A, C, D, E). Statement B is false because alleles DO show expression and both characters are recovered in F2 (this describes the Law of Segregation, not Dominance). Hence A, C, D and E only are correct. NCERT Reference: NCERT Class XII, Ch 4, p.59, lines 9-19: "4.2.1 Law of Dominance (i) Characters are controlled by discrete units called factors. (ii) Factors occur in pairs. (iii) In a dissimilar pair of factors one member of the pair dominates (dominant) the other (recessive). The law of dominance is used to explain the expression of only one of the parental characters in a monohybrid cross"