MENDEL'S DIHYBRID CROSS 09 HEREDITY AND EVOLUTION Class 10th Biology (Practice Sheet) 1 In a dihybrid cross, what is the genotype of the F1 generation when one parent is homozygous dominant for both traits (RRYY) and the other is homozygous recessive (rryy)? A. Rr Yy B. RRYY C. Rryy D. Rryy 2 What is the phenotype ratio in the F2 generation of a dihybrid cross, considering the classical Mendelian ratios? A. 1 : 2 : 1 B. 3 : 1 C. 9 : 3 : 3 : 1 D. 2 : 1 3 What conclusion did Mendel draw from his dihybrid crosses regarding the inheritance of traits? A. Genes are always inherited together. B. Traits are inherited independently. C. Dominant traits always skip a generation. D. Recessive traits are always expressed in the F1 generation. 4 According to Mendel's law of segregation, what happens during the formation of gametes? A. Alleles segregate randomly during fertilization. B. Two copies of each hereditary factor segregate during gamete production. C. Dominant alleles always segregate from recessive alleles. D. Gametes inherit traits as a combination of both parental alleles. 5 In a dihybrid cross, if the genotype of the parental plants is "YYRR" and "yyrr," what will be the genotype of the F1 generation? A. YyRr B. YYrr C. YyRR D. yyRr 6 In a dihybrid cross between RRYY and rryy, the number of RrYy F2 genotypes will be 7 On performing a test cross, 1:1 phenotypic ratio is obtained in the offspring; what that indicates? 8 Explain the difference between incomplete dominance and codominance with examples. 9 In a dihybrid cross, if you get 9:3:3:1 ratio it denotes that? 10 Heterozygous tall (Tt) is crossed with homozygous tall (TT). Percentage of heterozygous tall in the progeny would be Page 1 Email: Phone No: Website:
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