In Drosophila, grey body (G) is dominant over black body (g) and long wing (L) is dominant over vestigial wing (l). A dihybrid cross between two flies heterozygous for both traits is performed. If the two genes assort independently, how many of 160 expected offspring will have black body and vestigial wings?

In a standard dihybrid cross (GgLl × GgLl), the phenotypic ratio is 9 grey-long : 3 grey-vestigial : 3 black-long : 1 black-vestigial. The double recessive (black body, vestigial wing) appears in 1/16 of offspring. Therefore, 1/16 × 160 = 10 offspring. Options B, C, and D correspond to the 3/16, 4/16 (incorrect grouping), and 9/16 fractions respectively.