A genetic change that caused a certain Hox gene to be expressed ...

[penguins]

A genetic change that caused a certain Hox gene to be expressed along the tip of a vertebrate limb bud instead of farther back helped make possible the evolution of the tetrapod limb. This type of change is illustrative of
A) the influence of environment on development.
B) paedomorphosis.
C) a change in a developmental gene or its regulation that altered the spatial organization of body parts.
D) heterochrony.
E) gene duplication.

[Millan]

I know it's C, we did this last week

[penguins]

Thank you, thank you!!