-Dll Is a Gene Known to Direct Limb Development in the Fruit

Multiple Choice

-Dll is a gene known to direct limb development in the fruit fly. Researchers studying this gene have found that it is also expressed in developing appendages in animals from many other phyla, supporting the hypothesis that all animal appendages may be homologous. However, suppose researchers looking at Dll activity had instead found the results shown in the preceding table. These results suggest instead that ________.

A) Dll is not actually involved in appendage development
B) appendages evolved separately in protostomes and deuterostomes
C) appendages coevolved with segmentation
D) all animal appendages are homologous