Scientists, looking at the range of beak shapes and sizes across different finch species, observed that the thicker beak expressed a gene known as BMP4 early in development. To verify that the BMP4 gene itself could trigger the growth of bigger beaks, researchers increased the production of BMP4 in the developing beaks of chicken embryos. Which of the following results would explain why BMP4-treated chicks began growing wider, taller beaks?
A) Change to the genome induces radical changes in form.
B) New genes arise every time a new species arises.
C) Development cannot change morphology.
D) BMP4 is a homeotic gene.