Salamanders Normally Go Through a Juvenile Stage in Which They

Multiple Choice

Salamanders normally go through a juvenile stage in which they have external gills.Most salamanders lose these gills when they develop into adults, but axolotl salamanders retain gills into adulthood by suppressing metamorphosis.This is an example of

A) gene duplication.
B) co-opting a gene for a new function.
C) homeosis.
D) heterochrony.